diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-02 00:59:17 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-02 00:59:17 +0400 |
| commit | 15385dfe7e0fa6866b204dd0d14aec2cc48fc0a7 (patch) | |
| tree | 3ddcb000ec3b82f672fa892e8e44b1be4a5ebb33 /arch/x86/realmode | |
| parent | a57d985e378ca69f430b85852e4187db3698a89e (diff) | |
| parent | b2cc2a074de75671bbed5e2dda67a9252ef353ea (diff) | |
| download | linux-15385dfe7e0fa6866b204dd0d14aec2cc48fc0a7.tar.xz | |
Merge branch 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/smap support from Ingo Molnar:
"This adds support for the SMAP (Supervisor Mode Access Prevention) CPU
feature on Intel CPUs: a hardware feature that prevents unintended
user-space data access from kernel privileged code.
It's turned on automatically when possible.
This, in combination with SMEP, makes it even harder to exploit kernel
bugs such as NULL pointer dereferences."
Fix up trivial conflict in arch/x86/kernel/entry_64.S due to newly added
includes right next to each other.
* 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, smep, smap: Make the switching functions one-way
x86, suspend: On wakeup always initialize cr4 and EFER
x86-32: Start out eflags and cr4 clean
x86, smap: Do not abuse the [f][x]rstor_checking() functions for user space
x86-32, smap: Add STAC/CLAC instructions to 32-bit kernel entry
x86, smap: Reduce the SMAP overhead for signal handling
x86, smap: A page fault due to SMAP is an oops
x86, smap: Turn on Supervisor Mode Access Prevention
x86, smap: Add STAC and CLAC instructions to control user space access
x86, uaccess: Merge prototypes for clear_user/__clear_user
x86, smap: Add a header file with macros for STAC/CLAC
x86, alternative: Add header guards to <asm/alternative-asm.h>
x86, alternative: Use .pushsection/.popsection
x86, smap: Add CR4 bit for SMAP
x86-32, mm: The WP test should be done on a kernel page
Diffstat (limited to 'arch/x86/realmode')
| -rw-r--r-- | arch/x86/realmode/rm/wakeup.h | 2 | ||||
| -rw-r--r-- | arch/x86/realmode/rm/wakeup_asm.S | 29 |
2 files changed, 21 insertions, 10 deletions
diff --git a/arch/x86/realmode/rm/wakeup.h b/arch/x86/realmode/rm/wakeup.h index 9317e0042f24..7dd86a419f5d 100644 --- a/arch/x86/realmode/rm/wakeup.h +++ b/arch/x86/realmode/rm/wakeup.h @@ -36,5 +36,7 @@ extern struct wakeup_header wakeup_header; /* Wakeup behavior bits */ #define WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE 0 +#define WAKEUP_BEHAVIOR_RESTORE_CR4 1 +#define WAKEUP_BEHAVIOR_RESTORE_EFER 2 #endif /* ARCH_X86_KERNEL_ACPI_RM_WAKEUP_H */ diff --git a/arch/x86/realmode/rm/wakeup_asm.S b/arch/x86/realmode/rm/wakeup_asm.S index 8905166b0bbb..e56479e58053 100644 --- a/arch/x86/realmode/rm/wakeup_asm.S +++ b/arch/x86/realmode/rm/wakeup_asm.S @@ -74,9 +74,18 @@ ENTRY(wakeup_start) lidtl wakeup_idt - /* Clear the EFLAGS */ - pushl $0 + /* Clear the EFLAGS but remember if we have EFLAGS.ID */ + movl $X86_EFLAGS_ID, %ecx + pushl %ecx popfl + pushfl + popl %edi + pushl $0 + popfl + pushfl + popl %edx + xorl %edx, %edi + andl %ecx, %edi /* %edi is zero iff CPUID & %cr4 are missing */ /* Check header signature... */ movl signature, %eax @@ -93,8 +102,8 @@ ENTRY(wakeup_start) /* Restore MISC_ENABLE before entering protected mode, in case BIOS decided to clear XD_DISABLE during S3. */ - movl pmode_behavior, %eax - btl $WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE, %eax + movl pmode_behavior, %edi + btl $WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE, %edi jnc 1f movl pmode_misc_en, %eax @@ -110,15 +119,15 @@ ENTRY(wakeup_start) movl pmode_cr3, %eax movl %eax, %cr3 - movl pmode_cr4, %ecx - jecxz 1f - movl %ecx, %cr4 + btl $WAKEUP_BEHAVIOR_RESTORE_CR4, %edi + jz 1f + movl pmode_cr4, %eax + movl %eax, %cr4 1: + btl $WAKEUP_BEHAVIOR_RESTORE_EFER, %edi + jz 1f movl pmode_efer, %eax movl pmode_efer + 4, %edx - movl %eax, %ecx - orl %edx, %ecx - jz 1f movl $MSR_EFER, %ecx wrmsr 1: |