diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2020-01-03 12:39:34 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-01-10 18:55:01 +0100 |
| commit | 12dc9e154dbe18db337c9f7e4b1d40128e675f0f (patch) | |
| tree | e9007e2cdfb006374b268b796efc142eaab79927 /arch/x86/boot/compressed/head_64.S | |
| parent | 57ad87ddce79b6d54f8e442d0ecf4b5bbe8c5a9e (diff) | |
efi/libstub: Fix boot argument handling in mixed mode entry code
The mixed mode refactor actually broke mixed mode by failing to
pass the bootparam structure to startup_32(). This went unnoticed
because it apparently has a high tolerance for being passed random
junk, and still boots fine in some cases. So let's fix this by
populating %esi as required when entering via efi32_stub_entry,
and while at it, preserve the arguments themselves instead of their
address in memory (via the stack pointer) since that memory could
be clobbered before we get to it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Matthew Garrett <mjg59@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20200103113953.9571-2-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index a6f3ee9ca61d..44a6bb6964b5 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -208,13 +208,12 @@ SYM_FUNC_START(startup_32) pushl $__KERNEL_CS leal startup_64(%ebp), %eax #ifdef CONFIG_EFI_MIXED - movl efi32_boot_args(%ebp), %ebx - cmp $0, %ebx + movl efi32_boot_args(%ebp), %edi + cmp $0, %edi jz 1f leal handover_entry(%ebp), %eax - movl 0(%ebx), %edi - movl 4(%ebx), %esi - movl 8(%ebx), %edx + movl %esi, %edx + movl efi32_boot_args+4(%ebp), %esi movl $0x0, %ecx 1: #endif @@ -232,12 +231,16 @@ SYM_FUNC_END(startup_32) .org 0x190 SYM_FUNC_START(efi32_stub_entry) add $0x4, %esp /* Discard return address */ + popl %ecx + popl %edx + popl %esi call 1f 1: pop %ebp subl $1b, %ebp - movl %esp, efi32_boot_args(%ebp) + movl %ecx, efi32_boot_args(%ebp) + movl %edx, efi32_boot_args+4(%ebp) sgdtl efi32_boot_gdt(%ebp) /* Disable paging */ @@ -628,7 +631,7 @@ SYM_DATA_START_LOCAL(gdt) SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) #ifdef CONFIG_EFI_MIXED -SYM_DATA_LOCAL(efi32_boot_args, .long 0) +SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0) #endif /* |