From: Joerg Roedel <jroedel@xxxxxxx> Add the cr3 switches between the kernel and the user page-table when PTI is enabled. Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> --- arch/x86/entry/entry_32.S | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 14018eeb11c3..6a1d9f1e1f89 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -221,6 +221,25 @@ POP_GS_EX .endm +#define PTI_SWITCH_MASK (1 << PAGE_SHIFT) + +.macro SWITCH_TO_KERNEL_CR3 + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI + movl %cr3, %edi + andl $(~PTI_SWITCH_MASK), %edi + movl %edi, %cr3 +.Lend_\@: +.endm + +.macro SWITCH_TO_USER_CR3 + ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI + mov %cr3, %edi + /* Flip the PGD to the user version */ + orl $(PTI_SWITCH_MASK), %edi + mov %edi, %cr3 +.Lend_\@: +.endm + /* * Switch from the entry-trampline stack to the kernel stack of the * running task. @@ -240,6 +259,7 @@ .endif pushl %edi + SWITCH_TO_KERNEL_CR3 movl %esp, %edi /* @@ -309,9 +329,12 @@ .endif pushl 4(%edi) /* fs */ + pushl (%edi) /* edi */ + + SWITCH_TO_USER_CR3 /* Restore user %edi and user %fs */ - movl (%edi), %edi + popl %edi popl %fs .Lend_\@: -- 2.13.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
