diff options
Diffstat (limited to 'arch/x86/entry/calling.h')
| -rw-r--r-- | arch/x86/entry/calling.h | 212 |
1 files changed, 164 insertions, 48 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 6e160031cfea..3f48f695d5e6 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -1,6 +1,11 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <linux/jump_label.h> #include <asm/unwind_hints.h> +#include <asm/cpufeatures.h> +#include <asm/page_types.h> +#include <asm/percpu.h> +#include <asm/asm-offsets.h> +#include <asm/processor-flags.h> /* @@ -142,56 +147,25 @@ For 32-bit we have the following conventions - kernel is built with UNWIND_HINT_REGS offset=\offset .endm - .macro RESTORE_EXTRA_REGS offset=0 - movq 0*8+\offset(%rsp), %r15 - movq 1*8+\offset(%rsp), %r14 - movq 2*8+\offset(%rsp), %r13 - movq 3*8+\offset(%rsp), %r12 - movq 4*8+\offset(%rsp), %rbp - movq 5*8+\offset(%rsp), %rbx - UNWIND_HINT_REGS offset=\offset extra=0 - .endm - - .macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1 - .if \rstor_r11 - movq 6*8(%rsp), %r11 - .endif - .if \rstor_r8910 - movq 7*8(%rsp), %r10 - movq 8*8(%rsp), %r9 - movq 9*8(%rsp), %r8 - .endif - .if \rstor_rax - movq 10*8(%rsp), %rax - .endif - .if \rstor_rcx - movq 11*8(%rsp), %rcx - .endif - .if \rstor_rdx - movq 12*8(%rsp), %rdx - .endif - movq 13*8(%rsp), %rsi - movq 14*8(%rsp), %rdi - UNWIND_HINT_IRET_REGS offset=16*8 - .endm - .macro RESTORE_C_REGS - RESTORE_C_REGS_HELPER 1,1,1,1,1 - .endm - .macro RESTORE_C_REGS_EXCEPT_RAX - RESTORE_C_REGS_HELPER 0,1,1,1,1 - .endm - .macro RESTORE_C_REGS_EXCEPT_RCX - RESTORE_C_REGS_HELPER 1,0,1,1,1 - .endm - .macro RESTORE_C_REGS_EXCEPT_R11 - RESTORE_C_REGS_HELPER 1,1,0,1,1 - .endm - .macro RESTORE_C_REGS_EXCEPT_RCX_R11 - RESTORE_C_REGS_HELPER 1,0,0,1,1 + .macro POP_EXTRA_REGS + popq %r15 + popq %r14 + popq %r13 + popq %r12 + popq %rbp + popq %rbx .endm - .macro REMOVE_PT_GPREGS_FROM_STACK addskip=0 - subq $-(15*8+\addskip), %rsp + .macro POP_C_REGS + popq %r11 + popq %r10 + popq %r9 + popq %r8 + popq %rax + popq %rcx + popq %rdx + popq %rsi + popq %rdi .endm .macro icebp @@ -218,6 +192,148 @@ For 32-bit we have the following conventions - kernel is built with #endif .endm +#ifdef CONFIG_PAGE_TABLE_ISOLATION + +/* + * PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two + * halves: + */ +#define PTI_USER_PGTABLE_BIT PAGE_SHIFT +#define PTI_USER_PGTABLE_MASK (1 << PTI_USER_PGTABLE_BIT) +#define PTI_USER_PCID_BIT X86_CR3_PTI_PCID_USER_BIT +#define PTI_USER_PCID_MASK (1 << PTI_USER_PCID_BIT) +#define PTI_USER_PGTABLE_AND_PCID_MASK (PTI_USER_PCID_MASK | PTI_USER_PGTABLE_MASK) + +.macro SET_NOFLUSH_BIT reg:req + bts $X86_CR3_PCID_NOFLUSH_BIT, \reg +.endm + +.macro ADJUST_KERNEL_CR3 reg:req + ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID + /* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */ + andq $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg +.endm + +.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI + mov %cr3, \scratch_reg + ADJUST_KERNEL_CR3 \scratch_reg + mov \scratch_reg, %cr3 +.Lend_\@: +.endm + +#define THIS_CPU_user_pcid_flush_mask \ + PER_CPU_VAR(cpu_tlbstate) + TLB_STATE_user_pcid_flush_mask + +.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI + mov %cr3, \scratch_reg + + ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID + + /* + * Test if the ASID needs a flush. + */ + movq \scratch_reg, \scratch_reg2 + andq $(0x7FF), \scratch_reg /* mask ASID */ + bt \scratch_reg, THIS_CPU_user_pcid_flush_mask + jnc .Lnoflush_\@ + + /* Flush needed, clear the bit */ + btr \scratch_reg, THIS_CPU_user_pcid_flush_mask + movq \scratch_reg2, \scratch_reg + jmp .Lwrcr3_pcid_\@ + +.Lnoflush_\@: + movq \scratch_reg2, \scratch_reg + SET_NOFLUSH_BIT \scratch_reg + +.Lwrcr3_pcid_\@: + /* Flip the ASID to the user version */ + orq $(PTI_USER_PCID_MASK), \scratch_reg + +.Lwrcr3_\@: + /* Flip the PGD to the user version */ + orq $(PTI_USER_PGTABLE_MASK), \scratch_reg + mov \scratch_reg, %cr3 +.Lend_\@: +.endm + +.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req + pushq %rax + SWITCH_TO_USER_CR3_NOSTACK scratch_reg=\scratch_reg scratch_reg2=%rax + popq %rax +.endm + +.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req + ALTERNATIVE "jmp .Ldone_\@", "", X86_FEATURE_PTI + movq %cr3, \scratch_reg + movq \scratch_reg, \save_reg + /* + * Test the user pagetable bit. If set, then the user page tables + * are active. If clear CR3 already has the kernel page table + * active. + */ + bt $PTI_USER_PGTABLE_BIT, \scratch_reg + jnc .Ldone_\@ + + ADJUST_KERNEL_CR3 \scratch_reg + movq \scratch_reg, %cr3 + +.Ldone_\@: +.endm + +.macro RESTORE_CR3 scratch_reg:req save_reg:req + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI + + ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID + + /* + * KERNEL pages can always resume with NOFLUSH as we do + * explicit flushes. + */ + bt $PTI_USER_PGTABLE_BIT, \save_reg + jnc .Lnoflush_\@ + + /* + * Check if there's a pending flush for the user ASID we're + * about to set. + */ + movq \save_reg, \scratch_reg + andq $(0x7FF), \scratch_reg + bt \scratch_reg, THIS_CPU_user_pcid_flush_mask + jnc .Lnoflush_\@ + + btr \scratch_reg, THIS_CPU_user_pcid_flush_mask + jmp .Lwrcr3_\@ + +.Lnoflush_\@: + SET_NOFLUSH_BIT \save_reg + +.Lwrcr3_\@: + /* + * The CR3 write could be avoided when not changing its value, + * but would require a CR3 read *and* a scratch register. + */ + movq \save_reg, %cr3 +.Lend_\@: +.endm + +#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */ + +.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req +.endm +.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req +.endm +.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req +.endm +.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req +.endm +.macro RESTORE_CR3 scratch_reg:req save_reg:req +.endm + +#endif + #endif /* CONFIG_X86_64 */ /* |