wireguard-linux/arch/powerpc/kernel/head_32.S, branch jd/unified-crypt-queue

powerpc/32s: reorder Linux PTE bits to better match Hash PTE bits.

2020-03-25T01:09:27Z

Reorder Linux PTE bits to (almost) match Hash PTE bits. RW Kernel : PP = 00 RO Kernel : PP = 00 RW User : PP = 01 RO User : PP = 11 So naturally, we should have _PAGE_USER = 0x001 _PAGE_RW = 0x002 Today 0x001 and 0x002 and _PAGE_PRESENT and _PAGE_HASHPTE which both are software only bits. Switch _PAGE_USER and _PAGE_PRESET Switch _PAGE_RW and _PAGE_HASHPTE This allows to remove a few insns. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/c4d6c18a7f8d9d3b899bc492f55fbc40ef38896a.1583861325.git.christophe.leroy@c-s.fr

powerpc/32s: Fix DSI and ISI exceptions for CONFIG_VMAP_STACK

2020-02-18T10:31:11Z

hash_page() needs to read page tables from kernel memory. When entire kernel memory is mapped by BATs, which is normally the case when CONFIG_STRICT_KERNEL_RWX is not set, it works even if the page hosting the page table is not referenced in the MMU hash table. However, if the page where the page table resides is not covered by a BAT, a DSI fault can be encountered from hash_page(), and it loops forever. This can happen when CONFIG_STRICT_KERNEL_RWX is selected and the alignment of the different regions is too small to allow covering the entire memory with BATs. This also happens when CONFIG_DEBUG_PAGEALLOC is selected or when booting with 'nobats' flag. Also, if the page containing the kernel stack is not present in the MMU hash table, registers cannot be saved and a recursive DSI fault is encountered. To allow hash_page() to properly do its job at all time and load the MMU hash table whenever needed, it must run with data MMU disabled. This means it must be called before re-enabling data MMU. To allow this, registers clobbered by hash_page() and create_hpte() have to be saved in the thread struct together with SRR0, SSR1, DAR and DSISR. It is also necessary to ensure that DSI prolog doesn't overwrite regs saved by prolog of the current running exception. That means: - DSI can only use SPRN_SPRG_SCRATCH0 - Exceptions must free SPRN_SPRG_SCRATCH0 before writing to the stack. This also fixes the Oops reported by Erhard when create_hpte() is called by add_hash_page(). Due to prolog size increase, a few more exceptions had to get split in two parts. Fixes: cd08f109e262 ("powerpc/32s: Enable CONFIG_VMAP_STACK") Reported-by: Erhard F. Signed-off-by: Christophe Leroy Tested-by: Erhard F. Tested-by: Larry Finger Signed-off-by: Michael Ellerman Link: https://bugzilla.kernel.org/show_bug.cgi?id=206501 Link: https://lore.kernel.org/r/64a4aa44686e9fd4b01333401367029771d9b231.1581761633.git.christophe.leroy@c-s.fr

powerpc/32s: Enable CONFIG_VMAP_STACK

2020-01-27T11:37:24Z

A few changes to retrieve DAR and DSISR from struct regs instead of retrieving them directly, as they may have changed due to a TLB miss. Also modifies hash_page() and friends to work with virtual data addresses instead of physical ones. Same on load_up_fpu() and load_up_altivec(). Signed-off-by: Christophe Leroy [mpe: Fix tovirt_vmstack call in head_32.S to fix CHRP build] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2e2509a242fd5f3e23df4a06530c18060c4d321e.1576916812.git.christophe.leroy@c-s.fr

powerpc/32s: Avoid crossing page boundary while changing SRR0/1.

2020-01-27T11:37:03Z

Trying VMAP_STACK with KVM, vmlinux was not starting. This was due to SRR0 and SRR1 clobbered by an ISI due to the rfi being in a different page than the mtsrr0/1: c0003fe0 : c0003fe0: 38 83 00 54 addi r4,r3,84 c0003fe4: 7c 60 00 a6 mfmsr r3 c0003fe8: 70 60 00 30 andi. r0,r3,48 c0003fec: 4d 82 00 20 beqlr c0003ff0: 7c 63 00 78 andc r3,r3,r0 c0003ff4: 7c 9a 03 a6 mtsrr0 r4 c0003ff8: 7c 7b 03 a6 mtsrr1 r3 c0003ffc: 7c 00 04 ac hwsync c0004000: 4c 00 00 64 rfi Align the 4 instruction block used to deactivate MMU to order 4, so that the block never crosses a page boundary. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/30d2cda111b7977227fff067fa7e358440e2b3a4.1576916812.git.christophe.leroy@c-s.fr

powerpc/32s: Reorganise DSI handler.

2020-01-27T11:36:59Z

The part decidated to handling hash_page() is fully unneeded for processors not having real hash pages like the 603. Lets enlarge the content of the feature fixup, and provide an alternative which jumps directly instead of getting NIPs. Also, in preparation of VMAP stacks, the end of DSI handler has moved to later in the code as it won't fit anymore once VMAP stacks are there. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/c31b22c91af8b011d0a4fd9e52ad6afb4b593f71.1576916812.git.christophe.leroy@c-s.fr

powerpc/32: add a macro to get and/or save DAR and DSISR on stack.

2020-01-26T11:15:09Z

Refactor reading and saving of DAR and DSISR in exception vectors. This will ease the implementation of VMAP stack. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1286b3e51b07727c6b4b05f2df9af3f9b1717fb5.1576916812.git.christophe.leroy@c-s.fr

powerpc/32: save DEAR/DAR before calling handle_page_fault

2020-01-26T11:15:09Z

handle_page_fault() is the only function that save DAR/DEAR itself. Save DAR/DEAR before calling handle_page_fault() to prepare for VMAP stack which will require to save even before. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/3a4d58d378091086f00fde42b59610c80289e120.1576916812.git.christophe.leroy@c-s.fr

powerpc/32: Add EXCEPTION_PROLOG_0 in head_32.h

2020-01-26T11:15:08Z

This patch creates a macro for the very first part of exception prolog, this will help when implementing CONFIG_VMAP_STACK Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2249fe62f481121a180e9655ad2b998093f318f3.1576916812.git.christophe.leroy@c-s.fr

powerpc/32s: use CONFIG_PPC_BOOK3S_601 instead of reading PVR

2019-08-28T13:19:33Z

Use CONFIG_PPC_BOOK3S_601 instead of reading PVR to know if it is a 601 or not. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/909c26db9facd7fe454695b303f952e019dd9eda.1566834712.git.christophe.leroy@c-s.fr

powerpc/603: Fix handling of the DIRTY flag

2019-08-20T11:22:21Z

If a page is already mapped RW without the DIRTY flag, the DIRTY flag is never set and a TLB store miss exception is taken forever. This is easily reproduced with the following app: void main(void) { volatile char *ptr = mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); *ptr = *ptr; } When DIRTY flag is not set, bail out of TLB miss handler and take a minor page fault which will set the DIRTY flag. Fixes: f8b58c64eaef ("powerpc/603: let's handle PAGE_DIRTY directly") Cc: stable@vger.kernel.org # v5.1+ Reported-by: Doug Crawford Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/80432f71194d7ee75b2f5043ecf1501cf1cca1f3.1566196646.git.christophe.leroy@c-s.fr