diff options
| author |   Joerg Roedel <jroedel@suse.de> | 2020-09-07 15:15:32 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2020-09-07 21:40:53 +0200 |
| commit | 7b99819dfb60268cc1c75f83c949bc4a09221bea (patch) | |
| tree | 77f448aef7f5e7fbd7d9d8344f341160caef83b2 /arch/x86/kernel/head_64.S | |
| parent | x86/head/64: Load GDT after switch to virtual addresses (diff) | |
| download | linux-dev-7b99819dfb60268cc1c75f83c949bc4a09221bea.tar.xz linux-dev-7b99819dfb60268cc1c75f83c949bc4a09221bea.zip | |
x86/head/64: Load segment registers earlier
Make sure segments are properly set up before setting up an IDT and
doing anything that might cause a #VC exception. This is later needed
for early exception handling.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-32-joro@8bytes.org
Diffstat (limited to 'arch/x86/kernel/head_64.S')
| -rw-r--r-- | arch/x86/kernel/head_64.S | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 03b03f266dc1..f402087a02ac 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -166,6 +166,32 @@ SYM_CODE_START(secondary_startup_64) */ lgdt early_gdt_descr(%rip) + /* set up data segments */ + xorl %eax,%eax + movl %eax,%ds + movl %eax,%ss + movl %eax,%es + + /* + * We don't really need to load %fs or %gs, but load them anyway + * to kill any stale realmode selectors. This allows execution + * under VT hardware. + */ + movl %eax,%fs + movl %eax,%gs + + /* Set up %gs. + * + * The base of %gs always points to fixed_percpu_data. If the + * stack protector canary is enabled, it is located at %gs:40. + * Note that, on SMP, the boot cpu uses init data section until + * the per cpu areas are set up. + */ + movl $MSR_GS_BASE,%ecx + movl initial_gs(%rip),%eax + movl initial_gs+4(%rip),%edx + wrmsr + /* Check if nx is implemented */ movl $0x80000001, %eax cpuid @@ -193,32 +219,6 @@ SYM_CODE_START(secondary_startup_64) pushq $0 popfq - /* set up data segments */ - xorl %eax,%eax - movl %eax,%ds - movl %eax,%ss - movl %eax,%es - - /* - * We don't really need to load %fs or %gs, but load them anyway - * to kill any stale realmode selectors. This allows execution - * under VT hardware. - */ - movl %eax,%fs - movl %eax,%gs - - /* Set up %gs. - * - * The base of %gs always points to fixed_percpu_data. If the - * stack protector canary is enabled, it is located at %gs:40. - * Note that, on SMP, the boot cpu uses init data section until - * the per cpu areas are set up. - */ - movl $MSR_GS_BASE,%ecx - movl initial_gs(%rip),%eax - movl initial_gs+4(%rip),%edx - wrmsr - /* rsi is pointer to real mode structure with interesting info. pass it to C */ movq %rsi, %rdi |