diff options
| author | Patrick Rudolph <patrick.rudolph@9elements.com> | 2021-11-30 18:34:32 +0100 |
|---|---|---|
| committer | Patrick Georgi <patrick@coreboot.org> | 2021-12-06 12:37:48 +0000 |
| commit | 5b334b88a635e46d47ce3f3b703d2470d6e8514c (patch) | |
| tree | e57abd4d22b9ccaa7c771de1ad18845991521b9f /src/cpu/x86/64bit | |
| parent | c7f0bca9c23ac8d96ffc5ec0fcaddf9190d7dbff (diff) | |
x86_64 assembly: Don't touch %gs
With CPU_INFO_V2 enabled %gs holds the pointer to the cpu_info struct,
so don't clobber it. Backup and restore %gs where possible.
Fixes a crash in MPinit seen after calling FSP-S.
Change-Id: If9fc999b34530de5d8b6ad27b9af25fc552e9420
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/59764
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Diffstat (limited to 'src/cpu/x86/64bit')
| -rw-r--r-- | src/cpu/x86/64bit/exit32.inc | 1 | ||||
| -rw-r--r-- | src/cpu/x86/64bit/mode_switch.S | 14 |
2 files changed, 10 insertions, 5 deletions
diff --git a/src/cpu/x86/64bit/exit32.inc b/src/cpu/x86/64bit/exit32.inc index 4d1149ee6c..3ac86a9df1 100644 --- a/src/cpu/x86/64bit/exit32.inc +++ b/src/cpu/x86/64bit/exit32.inc @@ -68,7 +68,6 @@ __longmode_compatibility: movl %eax, %es movl %eax, %ss movl %eax, %fs - movl %eax, %gs /* Disable paging. */ movl %cr0, %eax diff --git a/src/cpu/x86/64bit/mode_switch.S b/src/cpu/x86/64bit/mode_switch.S index eea104bcf3..c27f540ba3 100644 --- a/src/cpu/x86/64bit/mode_switch.S +++ b/src/cpu/x86/64bit/mode_switch.S @@ -15,6 +15,10 @@ protected_mode_call_narg: push %r14 push %r15 + /* Backup gs to stack */ + movl %gs, %eax + push %rax + /* Arguments to stack */ push %rdi push %rsi @@ -23,9 +27,9 @@ protected_mode_call_narg: #include <cpu/x86/64bit/exit32.inc> - movl -48(%ebp), %eax /* Argument count */ - movl -64(%ebp), %edx /* Argument 0 */ - movl -72(%ebp), %ecx /* Argument 1 */ + movl -56(%ebp), %eax /* Argument count */ + movl -72(%ebp), %edx /* Argument 0 */ + movl -80(%ebp), %ecx /* Argument 1 */ /* Align the stack */ andl $0xFFFFFFF0, %esp @@ -46,7 +50,7 @@ protected_mode_call_narg: pushl %edx /* Argument 0 */ 1: - movl -56(%ebp), %ebx /* Function to call */ + movl -64(%ebp), %ebx /* Function to call */ call *%ebx movl %eax, %ebx @@ -57,6 +61,8 @@ protected_mode_call_narg: movl %ebx, %eax /* Restore registers */ + mov -48(%rbp), %rbx + movl %ebx, %gs mov -40(%rbp), %r15 mov -32(%rbp), %r14 mov -24(%rbp), %r13 |