aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm64/include
AgeCommit message (Collapse)AuthorFilesLines
2021-12-16KVM: arm64: Implement kvm_pgtable_hyp_unmap() at EL2Will Deacon1-0/+21
Implement kvm_pgtable_hyp_unmap() which can be used to remove hypervisor stage-1 mappings at EL2. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211215161232.1480836-6-qperret@google.com
2021-12-14arm64/sve: Generalise vector length configuration prctl() for SMEMark Brown1-3/+3
In preparation for adding SME support update the bulk of the implementation for the vector length configuration prctl() calls to be independent of vector type. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20211210184133.320748-3-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: Use BTI C directly and unconditionallyMark Brown1-16/+6
Now we have a macro for BTI C that looks like a regular instruction change all the users of the current BTI_C macro to just emit a BTI C directly and remove the macro. This does mean that we now unconditionally BTI annotate all assembly functions, meaning that they are worse in this respect than code generated by the compiler. The overhead should be minimal for implementations with a reasonable HINT implementation. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20211214152714.2380849-4-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: Unconditionally override SYM_FUNC macrosMark Brown1-5/+11
Currently we only override the SYM_FUNC macros when we need to insert BTI C into them, do this unconditionally to make it more likely that we'll notice bugs in our override. Suggested-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20211214152714.2380849-3-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: Add macro version of the BTI instructionMark Brown2-6/+11
BTI is only available from v8.5 so we need to encode it using HINT in generic code and for older toolchains. Add an assembler macro based on one written by Mark Rutland which lets us use the mnemonic and update the existing users. Suggested-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20211214152714.2380849-2-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: atomics: lse: define RETURN ops in terms of FETCH opsMark Rutland1-34/+14
The FEAT_LSE atomic instructions include LD* instructions which return the original value of a memory location can be used to directly implement FETCH opertations. Each RETURN op is implemented as a copy of the corresponding FETCH op with a trailing instruction to generate the new value of the memory location. We only directly implement *_fetch_add*(), for which we have a trailing `add` instruction. As the compiler has no visibility of the `add`, this leads to less than optimal code generation when consuming the result. For example, the compiler cannot constant-fold the addition into later operations, and currently GCC 11.1.0 will compile: return __lse_atomic_sub_return(1, v) == 0; As: mov w1, #0xffffffff ldaddal w1, w2, [x0] add w1, w1, w2 cmp w1, #0x0 cset w0, eq // eq = none ret This patch improves this by replacing the `add` with C addition after the inline assembly block, e.g. ret += i; This allows the compiler to manipulate `i`. This permits the compiler to merge the `add` and `cmp` for the above, e.g. mov w1, #0xffffffff ldaddal w1, w1, [x0] cmp w1, #0x1 cset w0, eq // eq = none ret With this change the assembly for each RETURN op is identical to the corresponding FETCH op (including barriers and clobbers) so I've removed the inline assembly and rewritten each RETURN op in terms of the corresponding FETCH op, e.g. | static inline void __lse_atomic_add_return(int i, atomic_t *v) | { | return __lse_atomic_fetch_add(i, v) + i | } The new construction does not adversely affect the common case, and before and after this patch GCC 11.1.0 can compile: __lse_atomic_add_return(i, v) As: ldaddal w0, w2, [x1] add w0, w0, w2 ... while having the freedom to do better elsewhere. This is intended as an optimization and cleanup. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211210151410.2782645-6-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: atomics: lse: improve constraints for simple opsMark Rutland1-12/+18
We have overly conservative assembly constraints for the basic FEAT_LSE atomic instructions, and using more accurate and permissive constraints will allow for better code generation. The FEAT_LSE basic atomic instructions have come in two forms: LD{op}{order}{size} <Rs>, <Rt>, [<Rn>] ST{op}{order}{size} <Rs>, [<Rn>] The ST* forms are aliases of the LD* forms where: ST{op}{order}{size} <Rs>, [<Rn>] Is: LD{op}{order}{size} <Rs>, XZR, [<Rn>] For either form, both <Rs> and <Rn> are read but not written back to, and <Rt> is written with the original value of the memory location. Where (<Rt> == <Rs>) or (<Rt> == <Rn>), <Rt> is written *after* the other register value(s) are consumed. There are no UNPREDICTABLE or CONSTRAINED UNPREDICTABLE behaviours when any pair of <Rs>, <Rt>, or <Rn> are the same register. Our current inline assembly always uses <Rs> == <Rt>, treating this register as both an input and an output (using a '+r' constraint). This forces the compiler to do some unnecessary register shuffling and/or redundant value generation. For example, the compiler cannot reuse the <Rs> value, and currently GCC 11.1.0 will compile: __lse_atomic_add(1, a); __lse_atomic_add(1, b); __lse_atomic_add(1, c); As: mov w3, #0x1 mov w4, w3 stadd w4, [x0] mov w0, w3 stadd w0, [x1] stadd w3, [x2] We can improve this with more accurate constraints, separating <Rs> and <Rt>, where <Rs> is an input-only register ('r'), and <Rt> is an output-only value ('=r'). As <Rt> is written back after <Rs> is consumed, it does not need to be earlyclobber ('=&r'), leaving the compiler free to use the same register for both <Rs> and <Rt> where this is desirable. At the same time, the redundant 'r' constraint for `v` is removed, as the `+Q` constraint is sufficient. With this change, the above example becomes: mov w3, #0x1 stadd w3, [x0] stadd w3, [x1] stadd w3, [x2] I've made this change for the non-value-returning and FETCH ops. The RETURN ops have a multi-instruction sequence for which we cannot use the same constraints, and a subsequent patch will rewrite hte RETURN ops in terms of the FETCH ops, relying on the ability for the compiler to reuse the <Rs> value. This is intended as an optimization. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211210151410.2782645-5-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: atomics: lse: define ANDs in terms of ANDNOTsMark Rutland1-30/+4
The FEAT_LSE atomic instructions include atomic bit-clear instructions (`ldclr*` and `stclr*`) which can be used to directly implement ANDNOT operations. Each AND op is implemented as a copy of the corresponding ANDNOT op with a leading `mvn` instruction to apply a bitwise NOT to the `i` argument. As the compiler has no visibility of the `mvn`, this leads to less than optimal code generation when generating `i` into a register. For example, __lse_atomic_fetch_and(0xf, v) can be compiled to: mov w1, #0xf mvn w1, w1 ldclral w1, w1, [x2] This patch improves this by replacing the `mvn` with NOT in C before the inline assembly block, e.g. i = ~i; This allows the compiler to generate `i` into a register more optimally, e.g. mov w1, #0xfffffff0 ldclral w1, w1, [x2] With this change the assembly for each AND op is identical to the corresponding ANDNOT op (including barriers and clobbers), so I've removed the inline assembly and rewritten each AND op in terms of the corresponding ANDNOT op, e.g. | static inline void __lse_atomic_and(int i, atomic_t *v) | { | return __lse_atomic_andnot(~i, v); | } This is intended as an optimization and cleanup. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211210151410.2782645-4-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: atomics lse: define SUBs in terms of ADDsMark Rutland1-122/+58
The FEAT_LSE atomic instructions include atomic ADD instructions (`stadd*` and `ldadd*`), but do not include atomic SUB instructions, so we must build all of the SUB operations using the ADD instructions. We open-code these today, with each SUB op implemented as a copy of the corresponding ADD op with a leading `neg` instruction in the inline assembly to negate the `i` argument. As the compiler has no visibility of the `neg`, this leads to less than optimal code generation when generating `i` into a register. For example, __les_atomic_fetch_sub(1, v) can be compiled to: mov w1, #0x1 neg w1, w1 ldaddal w1, w1, [x2] This patch improves this by replacing the `neg` with negation in C before the inline assembly block, e.g. i = -i; This allows the compiler to generate `i` into a register more optimally, e.g. mov w1, #0xffffffff ldaddal w1, w1, [x2] With this change the assembly for each SUB op is identical to the corresponding ADD op (including barriers and clobbers), so I've removed the inline assembly and rewritten each SUB op in terms of the corresponding ADD op, e.g. | static inline void __lse_atomic_sub(int i, atomic_t *v) | { | __lse_atomic_add(-i, v); | } For clarity I've moved the definition of each SUB op immediately after the corresponding ADD op, and used a single macro to create the RETURN forms of both ops. This is intended as an optimization and cleanup. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211210151410.2782645-3-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-14arm64: atomics: format whitespace consistentlyMark Rutland2-50/+50
The code for the atomic ops is formatted inconsistently, and while this is not a functional problem it is rather distracting when working on them. Some have ops have consistent indentation, e.g. | #define ATOMIC_OP_ADD_RETURN(name, mb, cl...) \ | static inline int __lse_atomic_add_return##name(int i, atomic_t *v) \ | { \ | u32 tmp; \ | \ | asm volatile( \ | __LSE_PREAMBLE \ | " ldadd" #mb " %w[i], %w[tmp], %[v]\n" \ | " add %w[i], %w[i], %w[tmp]" \ | : [i] "+r" (i), [v] "+Q" (v->counter), [tmp] "=&r" (tmp) \ | : "r" (v) \ | : cl); \ | \ | return i; \ | } While others have negative indentation for some lines, and/or have misaligned trailing backslashes, e.g. | static inline void __lse_atomic_##op(int i, atomic_t *v) \ | { \ | asm volatile( \ | __LSE_PREAMBLE \ | " " #asm_op " %w[i], %[v]\n" \ | : [i] "+r" (i), [v] "+Q" (v->counter) \ | : "r" (v)); \ | } This patch makes the indentation consistent and also aligns the trailing backslashes. This makes the code easier to read for those (like myself) who are easily distracted by these inconsistencies. This is intended as a cleanup. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211210151410.2782645-2-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-13arm64: cpufeature: add HWCAP for FEAT_RPRESJoey Gouly2-0/+2
Add a new HWCAP to detect the Increased precision of Reciprocal Estimate and Reciprocal Square Root Estimate feature (FEAT_RPRES), introduced in Armv8.7. Also expose this to userspace in the ID_AA64ISAR2_EL1 feature register. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211210165432.8106-4-joey.gouly@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-13arm64: add ID_AA64ISAR2_EL1 sys registerJoey Gouly2-0/+16
This is a new ID register, introduced in 8.7. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Reiji Watanabe <reijiw@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211210165432.8106-3-joey.gouly@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-13arm64: cpufeature: add HWCAP for FEAT_AFPJoey Gouly3-0/+3
Add a new HWCAP to detect the Alternate Floating-point Behaviour feature (FEAT_AFP), introduced in Armv8.7. Also expose this to userspace in the ID_AA64MMFR1_EL1 feature register. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211210165432.8106-2-joey.gouly@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-13efi: Move efifb_setup_from_dmi() prototype from arch headersJavier Martinez Canillas1-1/+0
Commit 8633ef82f101 ("drivers/firmware: consolidate EFI framebuffer setup for all arches") made the Generic System Framebuffers (sysfb) driver able to be built on non-x86 architectures. But it left the efifb_setup_from_dmi() function prototype declaration in the architecture specific headers. This could lead to the following compiler warning as reported by the kernel test robot: drivers/firmware/efi/sysfb_efi.c:70:6: warning: no previous prototype for function 'efifb_setup_from_dmi' [-Wmissing-prototypes] void efifb_setup_from_dmi(struct screen_info *si, const char *opt) ^ drivers/firmware/efi/sysfb_efi.c:70:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void efifb_setup_from_dmi(struct screen_info *si, const char *opt) Fixes: 8633ef82f101 ("drivers/firmware: consolidate EFI framebuffer setup for all arches") Reported-by: kernel test robot <lkp@intel.com> Cc: <stable@vger.kernel.org> # 5.15.x Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Link: https://lore.kernel.org/r/20211126001333.555514-1-javierm@redhat.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2021-12-13Merge tag 'v5.16-rc5' into locking/core, to pick up fixesIngo Molnar5-16/+55
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-12-10arm64: Make some stacktrace functions privateMark Rutland1-6/+0
Now that open-coded stack unwinds have been converted to arch_stack_walk(), we no longer need to expose any of unwind_frame(), walk_stackframe(), or start_backtrace() outside of stacktrace.c. Make those functions private to stacktrace.c, removing their prototypes from <asm/stacktrace.h> and marking them static. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> Link: https://lore.kernel.org/r/20211129142849.3056714-10-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-10arm64: Add comment for stack_info::kr_curMark Rutland1-0/+4
We added stack_info::kr_cur in commit: cd9bc2c9258816dc ("arm64: Recover kretprobe modified return address in stacktrace") ... but didn't add anything in the corresponding comment block. For consistency, add a corresponding comment. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviwed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20211129142849.3056714-3-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-08KVM: arm64: Drop unused workaround_flags vcpu fieldMarc Zyngier1-3/+0
workaround_flags is a leftover from our earlier Spectre-v4 workaround implementation, and now serves no purpose. Get rid of the field and the corresponding asm-offset definition. Fixes: 29e8910a566a ("KVM: arm64: Simplify handling of ARCH_WORKAROUND_2") Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-08Merge branch 'kvm-on-hv-msrbm-fix' into HEADPaolo Bonzini4-14/+53
Merge bugfix for enlightened MSR Bitmap, before adding support to KVM for exposing the feature to nested guests.
2021-12-08KVM: Drop obsolete kvm_arch_vcpu_block_finish()Sean Christopherson1-1/+0
Drop kvm_arch_vcpu_block_finish() now that all arch implementations are nops. No functional change intended. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211009021236.4122790-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-08KVM: arm64: Move vGIC v4 handling for WFI out arch callback hookSean Christopherson1-0/+2
Move the put and reload of the vGIC out of the block/unblock callbacks and into a dedicated WFI helper. Functionally, this is nearly a nop as the block hook is called at the very beginning of kvm_vcpu_block(), and the only code in kvm_vcpu_block() after the unblock hook is to update the halt-polling controls, i.e. can only affect the next WFI. Back when the arch (un)blocking hooks were added by commits 3217f7c25bca ("KVM: Add kvm_arch_vcpu_{un}blocking callbacks) and d35268da6687 ("arm/arm64: KVM: arch_timer: Only schedule soft timer on vcpu_block"), the hooks were invoked only when KVM was about to "block", i.e. schedule out the vCPU. The use case at the time was to schedule a timer in the host based on the earliest timer in the guest in order to wake the blocking vCPU when the emulated guest timer fired. Commit accb99bcd0ca ("KVM: arm/arm64: Simplify bg_timer programming") reworked the timer logic to be even more precise, by waiting until the vCPU was actually scheduled out, and so move the timer logic from the (un)blocking hooks to vcpu_load/put. In the meantime, the hooks gained usage for enabling vGIC v4 doorbells in commit df9ba95993b9 ("KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source"), and added related logic for the VMCR in commit 5eeaf10eec39 ("KVM: arm/arm64: Sync ICH_VMCR_EL2 back when about to block"). Finally, commit 07ab0f8d9a12 ("KVM: Call kvm_arch_vcpu_blocking early into the blocking sequence") hoisted the (un)blocking hooks so that they wrapped KVM's halt-polling logic in addition to the core "block" logic. In other words, the original need for arch hooks to take action _only_ in the block path is long since gone. Cc: Oliver Upton <oupton@google.com> Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211009021236.4122790-11-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-07locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.hSebastian Andrzej Siewior1-1/+1
The printk header file includes ratelimit_types.h for its __ratelimit() based usage. It is required for the static initializer used in printk_ratelimited(). It uses a raw_spinlock_t and includes the spinlock_types.h. PREEMPT_RT substitutes spinlock_t with a rtmutex based implementation and so its spinlock_t implmentation (provided by spinlock_rt.h) includes rtmutex.h and atomic.h which leads to recursive includes where defines are missing. By including only the raw_spinlock_t defines it avoids the atomic.h related includes at this stage. An example on powerpc: | CALL scripts/atomic/check-atomics.sh |In file included from include/linux/bug.h:5, | from include/linux/page-flags.h:10, | from kernel/bounds.c:10: |arch/powerpc/include/asm/page_32.h: In function ‘clear_page’: |arch/powerpc/include/asm/bug.h:87:4: error: implicit declaration of function â=80=98__WARNâ=80=99 [-Werror=3Dimplicit-function-declaration] | 87 | __WARN(); \ | | ^~~~~~ |arch/powerpc/include/asm/page_32.h:48:2: note: in expansion of macro ‘WARN_ONâ€=99 | 48 | WARN_ON((unsigned long)addr & (L1_CACHE_BYTES - 1)); | | ^~~~~~~ |arch/powerpc/include/asm/bug.h:58:17: error: invalid application of ‘sizeofâ€=99 to incomplete type ‘struct bug_entryâ€=99 | 58 | "i" (sizeof(struct bug_entry)), \ | | ^~~~~~ |arch/powerpc/include/asm/bug.h:89:3: note: in expansion of macro ‘BUG_ENTRYâ€=99 | 89 | BUG_ENTRY(PPC_TLNEI " %4, 0", \ | | ^~~~~~~~~ |arch/powerpc/include/asm/page_32.h:48:2: note: in expansion of macro ‘WARN_ONâ€=99 | 48 | WARN_ON((unsigned long)addr & (L1_CACHE_BYTES - 1)); | | ^~~~~~~ |In file included from arch/powerpc/include/asm/ptrace.h:298, | from arch/powerpc/include/asm/hw_irq.h:12, | from arch/powerpc/include/asm/irqflags.h:12, | from include/linux/irqflags.h:16, | from include/asm-generic/cmpxchg-local.h:6, | from arch/powerpc/include/asm/cmpxchg.h:526, | from arch/powerpc/include/asm/atomic.h:11, | from include/linux/atomic.h:7, | from include/linux/rwbase_rt.h:6, | from include/linux/rwlock_types.h:55, | from include/linux/spinlock_types.h:74, | from include/linux/ratelimit_types.h:7, | from include/linux/printk.h:10, | from include/asm-generic/bug.h:22, | from arch/powerpc/include/asm/bug.h:109, | from include/linux/bug.h:5, | from include/linux/page-flags.h:10, | from kernel/bounds.c:10: |include/linux/thread_info.h: In function â=80=98copy_overflowâ=80=99: |include/linux/thread_info.h:210:2: error: implicit declaration of function â=80=98WARNâ=80=99 [-Werror=3Dimplicit-function-declaration] | 210 | WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); | | ^~~~ The WARN / BUG include pulls in printk.h and then ptrace.h expects WARN (from bug.h) which is not yet complete. Even hw_irq.h has WARN_ON() statements. On POWERPC64 there are missing atomic64 defines while building 32bit VDSO: | VDSO32C arch/powerpc/kernel/vdso32/vgettimeofday.o |In file included from include/linux/atomic.h:80, | from include/linux/rwbase_rt.h:6, | from include/linux/rwlock_types.h:55, | from include/linux/spinlock_types.h:74, | from include/linux/ratelimit_types.h:7, | from include/linux/printk.h:10, | from include/linux/kernel.h:19, | from arch/powerpc/include/asm/page.h:11, | from arch/powerpc/include/asm/vdso/gettimeofday.h:5, | from include/vdso/datapage.h:137, | from lib/vdso/gettimeofday.c:5, | from <command-line>: |include/linux/atomic-arch-fallback.h: In function ‘arch_atomic64_incâ€=99: |include/linux/atomic-arch-fallback.h:1447:2: error: implicit declaration of function ‘arch_atomic64_add’; did you mean ‘arch_atomic_add’? [-Werror=3Dimpl |icit-function-declaration] | 1447 | arch_atomic64_add(1, v); | | ^~~~~~~~~~~~~~~~~ | | arch_atomic_add The generic fallback is not included, atomics itself are not used. If kernel.h does not include printk.h then it comes later from the bug.h include. Allow asm/spinlock_types.h to be included from linux/spinlock_types_raw.h. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211129174654.668506-12-bigeasy@linutronix.de
2021-12-07Merge branch kvm-arm64/misc-5.17 into kvmarm-master/nextMarc Zyngier1-0/+1
* kvm-arm64/misc-5.17: : . : - Add minimal support for ARMv8.7's PMU extension : - Constify kvm_io_gic_ops : - Drop kvm_is_transparent_hugepage() prototype : . KVM: Drop stale kvm_is_transparent_hugepage() declaration KVM: arm64: Constify kvm_io_gic_ops KVM: arm64: Add minimal handling for the ARMv8.7 PMU Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-07Merge branch kvm-arm64/hyp-header-split into kvmarm-master/nextMarc Zyngier2-0/+72
* kvm-arm64/hyp-header-split: : . : Tidy up the header file usage for the nvhe hyp object so : that header files under arch/arm64/kvm/hyp/include are not : included by host code running at EL1. : . KVM: arm64: Move host EL1 code out of hyp/ directory KVM: arm64: Generate hyp_constants.h for the host arm64: Add missing include of asm/cpufeature.h to asm/mmu.h Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-06arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1Reiji Watanabe1-3/+5
Currently, mte_set_mem_tag_range() and mte_zero_clear_page_tags() use DC {GVA,GZVA} unconditionally. But, they should make sure that DCZID_EL0.DZP, which indicates whether or not use of those instructions is prohibited, is zero when using those instructions. Use ST{G,ZG,Z2G} instead when DCZID_EL0.DZP == 1. Fixes: 013bb59dbb7c ("arm64: mte: handle tags zeroing at page allocation time") Fixes: 3d0cca0b02ac ("kasan: speed up mte_set_mem_tag_range") Signed-off-by: Reiji Watanabe <reijiw@google.com> Link: https://lore.kernel.org/r/20211206004736.1520989-3-reijiw@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-12-06KVM: arm64: Move host EL1 code out of hyp/ directoryWill Deacon1-0/+71
kvm/hyp/reserved_mem.c contains host code executing at EL1 and is not linked into the hypervisor object. Move the file into kvm/pkvm.c and rework the headers so that the definitions shared between the host and the hypervisor live in asm/kvm_pkvm.h. Signed-off-by: Will Deacon <will@kernel.org> Tested-by: Fuad Tabba <tabba@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211202171048.26924-4-will@kernel.org
2021-12-06arm64: Add missing include of asm/cpufeature.h to asm/mmu.hWill Deacon1-0/+1
asm/mmu.h refers to cpus_have_const_cap() in the definition of arm64_kernel_unmapped_at_el0() so include asm/cpufeature.h directly rather than force all users of the header to do it themselves. Signed-off-by: Will Deacon <will@kernel.org> Tested-by: Fuad Tabba <tabba@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211202171048.26924-2-will@kernel.org
2021-12-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-2/+2
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-01KVM: arm64: Add minimal handling for the ARMv8.7 PMUMarc Zyngier1-0/+1
When running a KVM guest hosted on an ARMv8.7 machine, the host kernel complains that it doesn't know about the architected number of events. Fix it by adding the PMUver code corresponding to PMUv3 for ARMv8.7. Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com> Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211126115533.217903-1-maz@kernel.org
2021-12-01Merge branch kvm-arm64/fpsimd-tracking into kvmarm-master/nextMarc Zyngier2-16/+14
* kvm-arm64/fpsimd-tracking: : . : Simplify the handling of both the FP/SIMD and SVE state by : removing the need for mapping the thread at EL2, and by : dropping the tracking of the host's SVE state which is : always invalid by construction. : . arm64/fpsimd: Document the use of TIF_FOREIGN_FPSTATE by KVM KVM: arm64: Stop mapping current thread_info at EL2 KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATE KVM: arm64: Remove unused __sve_save_state KVM: arm64: Get rid of host SVE tracking/saving KVM: arm64: Reorder vcpu flag definitions Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-01KVM: arm64: Drop vcpu->arch.has_run_once for vcpu->pidMarc Zyngier1-3/+2
With the transition to kvm_arch_vcpu_run_pid_change() to handle the "run once" activities, it becomes obvious that has_run_once is now an exact shadow of vcpu->pid. Replace vcpu->arch.has_run_once with a new vcpu_has_run_once() helper that directly checks for vcpu->pid, and get rid of the now unused field. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-01KVM: arm64: Move kvm_arch_vcpu_run_pid_change() out of lineMarc Zyngier1-6/+1
Having kvm_arch_vcpu_run_pid_change() inline doesn't bring anything to the table. Move it next to kvm_vcpu_first_run_init(), which will be convenient for what is next to come. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-30Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds1-2/+2
Pull kvm fixes from Paolo Bonzini: "ARM64: - Fix constant sign extension affecting TCR_EL2 and preventing running on ARMv8.7 models due to spurious bits being set - Fix use of helpers using PSTATE early on exit by always sampling it as soon as the exit takes place - Move pkvm's 32bit handling into a common helper RISC-V: - Fix incorrect KVM_MAX_VCPUS value - Unmap stage2 mapping when deleting/moving a memslot x86: - Fix and downgrade BUG_ON due to uninitialized cache - Many APICv and MOVE_ENC_CONTEXT_FROM fixes - Correctly emulate TLB flushes around nested vmentry/vmexit and when the nested hypervisor uses VPID - Prevent modifications to CPUID after the VM has run - Other smaller bugfixes Generic: - Memslot handling bugfixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits) KVM: fix avic_set_running for preemptable kernels KVM: VMX: clear vmx_x86_ops.sync_pir_to_irr if APICv is disabled KVM: SEV: accept signals in sev_lock_two_vms KVM: SEV: do not take kvm->lock when destroying KVM: SEV: Prohibit migration of a VM that has mirrors KVM: SEV: Do COPY_ENC_CONTEXT_FROM with both VMs locked selftests: sev_migrate_tests: add tests for KVM_CAP_VM_COPY_ENC_CONTEXT_FROM KVM: SEV: move mirror status to destination of KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM KVM: SEV: initialize regions_list of a mirror VM KVM: SEV: cleanup locking for KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM KVM: SEV: do not use list_replace_init on an empty list KVM: x86: Use a stable condition around all VT-d PI paths KVM: x86: check PIR even for vCPUs with disabled APICv KVM: VMX: prepare sync_pir_to_irr for running with APICv disabled KVM: selftests: page_table_test: fix calculation of guest_test_phys_mem KVM: x86/mmu: Handle "default" period when selectively waking kthread KVM: MMU: shadow nested paging does not have PKU KVM: x86/mmu: Remove spurious TLB flushes in TDP MMU zap collapsible path KVM: x86/mmu: Use yield-safe TDP MMU root iter in MMU notifier unmapping KVM: X86: Use vcpu->arch.walk_mmu for kvm_mmu_invlpg() ...
2021-11-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski4-14/+53
drivers/net/ipa/ipa_main.c 8afc7e471ad3 ("net: ipa: separate disabling setup from modem stop") 76b5fbcd6b47 ("net: ipa: kill ipa_modem_init()") Duplicated include, drop one. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-25KVM: arm64: Avoid setting the upper 32 bits of TCR_EL2 and CPTR_EL2 to 1Catalin Marinas1-2/+2
Having a signed (1 << 31) constant for TCR_EL2_RES1 and CPTR_EL2_TCPAC causes the upper 32-bit to be set to 1 when assigning them to a 64-bit variable. Bit 32 in TCR_EL2 is no longer RES0 in ARMv8.7: with FEAT_LPA2 it changes the meaning of bits 49:48 and 9:8 in the stage 1 EL2 page table entries. As a result of the sign-extension, a non-VHE kernel can no longer boot on a model with ARMv8.7 enabled. CPTR_EL2 still has the top 32 bits RES0 but we should preempt any future problems Make these top bit constants unsigned as per commit df655b75c43f ("arm64: KVM: Avoid setting the upper 32 bits of VTCR_EL2 to 1"). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Chris January <Chris.January@arm.com> Cc: <stable@vger.kernel.org> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211125152014.2806582-1-catalin.marinas@arm.com
2021-11-24arm64: uaccess: avoid blocking within critical sectionsMark Rutland1-7/+41
As Vincent reports in: https://lore.kernel.org/r/20211118163417.21617-1-vincent.whitchurch@axis.com The put_user() in schedule_tail() can get stuck in a livelock, similar to a problem recently fixed on riscv in commit: 285a76bb2cf51b0c ("riscv: evaluate put_user() arg before enabling user access") In __raw_put_user() we have a critical section between uaccess_ttbr0_enable() and uaccess_ttbr0_disable() where we cannot safely call into the scheduler without having taken an exception, as schedule() and other scheduling functions will not save/restore the TTBR0 state. If either of the `x` or `ptr` arguments to __raw_put_user() contain a blocking call, we may call into the scheduler within the critical section. This can result in two problems: 1) The access within the critical section will occur without the required TTBR0 tables installed. This will fault, and where the required tables permit access, the access will be retried without the required tables, resulting in a livelock. 2) When TTBR0 SW PAN is in use, check_and_switch_context() does not modify TTBR0, leaving a stale value installed. The mappings of the blocked task will erroneously be accessible to regular accesses in the context of the new task. Additionally, if the tables are subsequently freed, local TLB maintenance required to reuse the ASID may be lost, potentially resulting in TLB corruption (e.g. in the presence of CnP). The same issue exists for __raw_get_user() in the critical section between uaccess_ttbr0_enable() and uaccess_ttbr0_disable(). A similar issue exists for __get_kernel_nofault() and __put_kernel_nofault() for the critical section between __uaccess_enable_tco_async() and __uaccess_disable_tco_async(), as the TCO state is not context-switched by direct calls into the scheduler. Here the TCO state may be lost from the context of the current task, resulting in unexpected asynchronous tag check faults. It may also be leaked to another task, suppressing expected tag check faults. To fix all of these cases, we must ensure that we do not directly call into the scheduler in their respective critical sections. This patch reworks __raw_put_user(), __raw_get_user(), __get_kernel_nofault(), and __put_kernel_nofault(), ensuring that parameters are evaluated outside of the critical sections. To make this requirement clear, comments are added describing the problem, and line spaces added to separate the critical sections from other portions of the macros. For __raw_get_user() and __raw_put_user() the `err` parameter is conditionally assigned to, and we must currently evaluate this in the critical section. This behaviour is relied upon by the signal code, which uses chains of put_user_error() and get_user_error(), checking the return value at the end. In all cases, the `err` parameter is a plain int rather than a more complex expression with a blocking call, so this is safe. In future we should try to clean up the `err` usage to remove the potential for this to be a problem. Aside from the changes to time of evaluation, there should be no functional change as a result of this patch. Reported-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Link: https://lore.kernel.org/r/20211118163417.21617-1-vincent.whitchurch@axis.com Fixes: f253d827f33c ("arm64: uaccess: refactor __{get,put}_user") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20211122125820.55286-1-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-11-23arch_topology: Remove unused topology_set_thermal_pressure() and relatedLukasz Luba1-1/+0
There is no need of this function (and related) since code has been converted to use the new arch_update_thermal_pressure() API. The old code can be removed. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-11-23arch_topology: Introduce thermal pressure update functionLukasz Luba1-0/+1
The thermal pressure is a mechanism which is used for providing information about reduced CPU performance to the scheduler. Usually code has to convert the value from frequency units into capacity units, which are understandable by the scheduler. Create a common conversion code which can be just used via a handy API. Internally, the topology_update_thermal_pressure() operates on frequency in MHz and max CPU frequency is taken from 'freq_factor' (per-cpu). Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Thara Gopinath <thara.gopinath@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-11-22KVM: arm64: Stop mapping current thread_info at EL2Marc Zyngier1-2/+0
Now that we can track an equivalent of TIF_FOREIGN_FPSTATE, drop the mapping of current's thread_info at EL2. Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-22KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATEMarc Zyngier1-0/+2
We currently have to maintain a mapping the thread_info structure at EL2 in order to be able to check the TIF_FOREIGN_FPSTATE flag. In order to eventually get rid of this, start with a vcpu flag that shadows the thread flag on each entry into the hypervisor. Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-22KVM: arm64: Remove unused __sve_save_stateMarc Zyngier1-1/+0
Now that we don't have any users left for __sve_save_state, remove it altogether. Should we ever need to save the SVE state from the hypervisor again, we can always re-introduce it. Suggested-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-22KVM: arm64: Get rid of host SVE tracking/savingMarc Zyngier1-1/+0
The SVE host tracking in KVM is pretty involved. It relies on a set of flags tracking the ownership of the SVE register, as well as that of the EL0 access. It is also pretty scary: __hyp_sve_save_host() computes a thread_struct pointer and obtains a sve_state which gets directly accessed without further ado, even on nVHE. How can this even work? The answer to that is that it doesn't, and that this is mostly dead code. Closer examination shows that on executing a syscall, userspace loses its SVE state entirely. This is part of the ABI. Another thing to notice is that although the kernel provides helpers such as kernel_neon_begin()/end(), they only deal with the FP/NEON state, and not SVE. Given that you can only execute a guest as the result of a syscall, and that the kernel cannot use SVE by itself, it becomes pretty obvious that there is never any host SVE state to save, and that this code is only there to increase confusion. Get rid of the TIF_SVE tracking and host save infrastructure altogether. Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-22KVM: arm64: Reorder vcpu flag definitionsMarc Zyngier1-12/+12
The vcpu arch flags are in an interesting, semi random order. As I have made the mistake of reusing a flag once, let's rework this in an order that I find a bit less confusing. Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski2-1/+2
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-17KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.cSean Christopherson1-3/+0
Call KVM's (un)register perf callbacks helpers directly from arm.c and delete perf.c No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211111020738.2512932-17-seanjc@google.com
2021-11-17KVM: Move x86's perf guest info callbacks to generic KVMSean Christopherson1-0/+10
Move x86's perf guest callbacks into common KVM, as they are semantically identical to arm64's callbacks (the only other such KVM callbacks). arm64 will convert to the common versions in a future patch. Implement the necessary arm64 arch hooks now to avoid having to provide stubs or a temporary #define (from x86) to avoid arm64 compilation errors when CONFIG_GUEST_PERF_EVENTS=y. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211111020738.2512932-13-seanjc@google.com
2021-11-17perf: Stop pretending that perf can handle multiple guest callbacksSean Christopherson1-2/+2
Drop the 'int' return value from the perf (un)register callbacks helpers and stop pretending perf can support multiple callbacks. The 'int' returns are not future proofing anything as none of the callers take action on an error. It's also not obvious that there will ever be co-tenant hypervisors, and if there are, that allowing multiple callbacks to be registered is desirable or even correct. Opportunistically rename callbacks=>cbs in the affected declarations to match their definitions. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lore.kernel.org/r/20211111020738.2512932-5-seanjc@google.com
2021-11-16arm64: mm: Fix VM_BUG_ON(mm != &init_mm) for trans_pgdPingfan Liu1-1/+1
trans_pgd_create_copy() can hit "VM_BUG_ON(mm != &init_mm)" in the function pmd_populate_kernel(). This is the combined consequence of commit 5de59884ac0e ("arm64: trans_pgd: pass NULL instead of init_mm to *_populate functions"), which replaced &init_mm with NULL and commit 59511cfd08f3 ("arm64: mm: use XN table mapping attributes for user/kernel mappings"), which introduced the VM_BUG_ON. Since the former sounds reasonable, it is better to work on the later. From the perspective of trans_pgd, two groups of functions are considered in the later one: pmd_populate_kernel() mm == NULL should be fixed, else it hits VM_BUG_ON() p?d_populate() mm == NULL means PXN, that is OK, since trans_pgd only copies a linear map, no execution will happen on the map. So it is good enough to just relax VM_BUG_ON() to disregard mm == NULL Fixes: 59511cfd08f3 ("arm64: mm: use XN table mapping attributes for user/kernel mappings") Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Cc: <stable@vger.kernel.org> # 5.13.x Cc: Ard Biesheuvel <ardb@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Matthias Brugger <mbrugger@suse.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://lore.kernel.org/r/20211112052214.9086-1-kernelfans@gmail.com Signed-off-by: Will Deacon <will@kernel.org>
2021-11-16arm64: ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTRMark Rutland2-6/+11
When CONFIG_FUNCTION_GRAPH_TRACER is selected and the function graph tracer is in use, unwind_frame() may erroneously associate a traced function with an incorrect return address. This can happen when starting an unwind from a pt_regs, or when unwinding across an exception boundary. This can be seen when recording with perf while the function graph tracer is in use. For example: | # echo function_graph > /sys/kernel/debug/tracing/current_tracer | # perf record -g -e raw_syscalls:sys_enter:k /bin/true | # perf report ... reports the callchain erroneously as: | el0t_64_sync | el0t_64_sync_handler | el0_svc_common.constprop.0 | perf_callchain | get_perf_callchain | syscall_trace_enter | syscall_trace_enter ... whereas when the function graph tracer is not in use, it reports: | el0t_64_sync | el0t_64_sync_handler | el0_svc | do_el0_svc | el0_svc_common.constprop.0 | syscall_trace_enter | syscall_trace_enter The underlying problem is that ftrace_graph_get_ret_stack() takes an index offset from the most recent entry added to the fgraph return stack. We start an unwind at offset 0, and increment the offset each time we encounter a rewritten return address (i.e. when we see `return_to_handler`). This is broken in two cases: 1) Between creating a pt_regs and starting the unwind, function calls may place entries on the stack, leaving an arbitrary offset which we can only determine by performing a full unwind from the caller of the unwind code (and relying on none of the unwind code being instrumented). This can result in erroneous entries being reported in a backtrace recorded by perf or kfence when the function graph tracer is in use. Currently show_regs() is unaffected as dump_backtrace() performs an initial unwind. 2) When unwinding across an exception boundary (whether continuing an unwind or starting a new unwind from regs), we currently always skip the LR of the interrupted context. Where this was live and contained a rewritten address, we won't consume the corresponding fgraph ret stack entry, leaving subsequent entries off-by-one. This can result in erroneous entries being reported in a backtrace performed by any in-kernel unwinder when that backtrace crosses an exception boundary, with entries after the boundary being reported incorrectly. This includes perf, kfence, show_regs(), panic(), etc. To fix this, we need to be able to uniquely identify each rewritten return address such that we can map this back to the original return address. We can use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR to associate each rewritten return address with a unique location on the stack. As the return address is passed in the LR (and so is not guaranteed a unique location in memory), we use the FP upon entry to the function (i.e. the address of the caller's frame record) as the return address pointer. Any nested call will have a different FP value as the caller must create its own frame record and update FP to point to this. Since ftrace_graph_ret_addr() requires the return address with the PAC stripped, the stripping of the PAC is moved before the fixup of the rewritten address. As we would unconditionally strip the PAC, moving this earlier is not harmful, and we can avoid a redundant strip in the return address fixup code. I've tested this with the perf case above, the ftrace selftests, and a number of ad-hoc unwinder tests. The tests all pass, and I have seen no unexpected behaviour as a result of this change. I've tested with pointer authentication under QEMU TCG where magic-sysrq+l correctly recovers the original return addresses. Note that this doesn't fix the issue of skipping a live LR at an exception boundary, which is a more general problem and requires more substantial rework. Were we to consume the LR in all cases this would result in warnings where the interrupted context's LR contains `return_to_handler`, but the FP has been altered, e.g. | func: | <--- ftrace entry ---> // logs FP & LR, rewrites LR | STP FP, LR, [SP, #-16]! | MOV FP, SP | <--- INTERRUPT ---> ... as ftrace_graph_get_ret_stack() fill not find a matching entry, triggering the WARN_ON_ONCE() in unwind_frame(). Link: https://lore.kernel.org/r/20211025164925.GB2001@C02TD0UTHF1T.local Link: https://lore.kernel.org/r/20211027132529.30027-1-mark.rutland@arm.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> Cc: Mark Brown <broonie@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20211029162245.39761-1-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2021-11-15Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski2-13/+1
Daniel Borkmann says: ==================== pull-request: bpf-next 2021-11-15 We've added 72 non-merge commits during the last 13 day(s) which contain a total of 171 files changed, 2728 insertions(+), 1143 deletions(-). The main changes are: 1) Add btf_type_tag attributes to bring kernel annotations like __user/__rcu to BTF such that BPF verifier will be able to detect misuse, from Yonghong Song. 2) Big batch of libbpf improvements including various fixes, future proofing APIs, and adding a unified, OPTS-based bpf_prog_load() low-level API, from Andrii Nakryiko. 3) Add ingress_ifindex to BPF_SK_LOOKUP program type for selectively applying the programmable socket lookup logic to packets from a given netdev, from Mark Pashmfouroush. 4) Remove the 128M upper JIT limit for BPF programs on arm64 and add selftest to ensure exception handling still works, from Russell King and Alan Maguire. 5) Add a new bpf_find_vma() helper for tracing to map an address to the backing file such as shared library, from Song Liu. 6) Batch of various misc fixes to bpftool, fixing a memory leak in BPF program dump, updating documentation and bash-completion among others, from Quentin Monnet. 7) Deprecate libbpf bpf_program__get_prog_info_linear() API and migrate its users as the API is heavily tailored around perf and is non-generic, from Dave Marchevsky. 8) Enable libbpf's strict mode by default in bpftool and add a --legacy option as an opt-out for more relaxed BPF program requirements, from Stanislav Fomichev. 9) Fix bpftool to use libbpf_get_error() to check for errors, from Hengqi Chen. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits) bpftool: Use libbpf_get_error() to check error bpftool: Fix mixed indentation in documentation bpftool: Update the lists of names for maps and prog-attach types bpftool: Fix indent in option lists in the documentation bpftool: Remove inclusion of utilities.mak from Makefiles bpftool: Fix memory leak in prog_dump() selftests/bpf: Fix a tautological-constant-out-of-range-compare compiler warning selftests/bpf: Fix an unused-but-set-variable compiler warning bpf: Introduce btf_tracing_ids bpf: Extend BTF_ID_LIST_GLOBAL with parameter for number of IDs bpftool: Enable libbpf's strict mode by default docs/bpf: Update documentation for BTF_KIND_TYPE_TAG support selftests/bpf: Clarify llvm dependency with btf_tag selftest selftests/bpf: Add a C test for btf_type_tag selftests/bpf: Rename progs/tag.c to progs/btf_decl_tag.c selftests/bpf: Test BTF_KIND_DECL_TAG for deduplication selftests/bpf: Add BTF_KIND_TYPE_TAG unit tests selftests/bpf: Test libbpf API function btf__add_type_tag() bpftool: Support BTF_KIND_TYPE_TAG libbpf: Support BTF_KIND_TYPE_TAG ... ==================== Link: https://lore.kernel.org/r/20211115162008.25916-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>