diff options
Diffstat (limited to 'arch/x86/entry/calling.h')
| -rw-r--r-- | arch/x86/entry/calling.h | 36 |
1 files changed, 19 insertions, 17 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 45a63e00a6af..3f48f695d5e6 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -198,8 +198,11 @@ For 32-bit we have the following conventions - kernel is built with * PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two * halves: */ -#define PTI_SWITCH_PGTABLES_MASK (1<<PAGE_SHIFT) -#define PTI_SWITCH_MASK (PTI_SWITCH_PGTABLES_MASK|(1<<X86_CR3_PTI_SWITCH_BIT)) +#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 @@ -208,7 +211,7 @@ For 32-bit we have the following conventions - kernel is built with .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_SWITCH_MASK), \reg + andq $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg .endm .macro SWITCH_TO_KERNEL_CR3 scratch_reg:req @@ -239,15 +242,19 @@ For 32-bit we have the following conventions - kernel is built with /* Flush needed, clear the bit */ btr \scratch_reg, THIS_CPU_user_pcid_flush_mask movq \scratch_reg2, \scratch_reg - jmp .Lwrcr3_\@ + 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 and ASID to the user version */ - orq $(PTI_SWITCH_MASK), \scratch_reg + /* Flip the PGD to the user version */ + orq $(PTI_USER_PGTABLE_MASK), \scratch_reg mov \scratch_reg, %cr3 .Lend_\@: .endm @@ -263,17 +270,12 @@ For 32-bit we have the following conventions - kernel is built with movq %cr3, \scratch_reg movq \scratch_reg, \save_reg /* - * Is the "switch mask" all zero? That means that both of - * these are zero: - * - * 1. The user/kernel PCID bit, and - * 2. The user/kernel "bit" that points CR3 to the - * bottom half of the 8k PGD - * - * That indicates a kernel CR3 value, not a user CR3. + * Test the user pagetable bit. If set, then the user page tables + * are active. If clear CR3 already has the kernel page table + * active. */ - testq $(PTI_SWITCH_MASK), \scratch_reg - jz .Ldone_\@ + bt $PTI_USER_PGTABLE_BIT, \scratch_reg + jnc .Ldone_\@ ADJUST_KERNEL_CR3 \scratch_reg movq \scratch_reg, %cr3 @@ -290,7 +292,7 @@ For 32-bit we have the following conventions - kernel is built with * KERNEL pages can always resume with NOFLUSH as we do * explicit flushes. */ - bt $X86_CR3_PTI_SWITCH_BIT, \save_reg + bt $PTI_USER_PGTABLE_BIT, \save_reg jnc .Lnoflush_\@ /* |