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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>
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parent
57ad87ddce
commit
12dc9e154d
1 changed files with 10 additions and 7 deletions
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@ -208,13 +208,12 @@ SYM_FUNC_START(startup_32)
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pushl $__KERNEL_CS
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leal startup_64(%ebp), %eax
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#ifdef CONFIG_EFI_MIXED
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movl efi32_boot_args(%ebp), %ebx
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cmp $0, %ebx
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movl efi32_boot_args(%ebp), %edi
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cmp $0, %edi
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jz 1f
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leal handover_entry(%ebp), %eax
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movl 0(%ebx), %edi
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movl 4(%ebx), %esi
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movl 8(%ebx), %edx
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movl %esi, %edx
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movl efi32_boot_args+4(%ebp), %esi
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movl $0x0, %ecx
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1:
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#endif
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@ -232,12 +231,16 @@ SYM_FUNC_END(startup_32)
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.org 0x190
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SYM_FUNC_START(efi32_stub_entry)
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add $0x4, %esp /* Discard return address */
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popl %ecx
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popl %edx
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popl %esi
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call 1f
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1: pop %ebp
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subl $1b, %ebp
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movl %esp, efi32_boot_args(%ebp)
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movl %ecx, efi32_boot_args(%ebp)
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movl %edx, efi32_boot_args+4(%ebp)
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sgdtl efi32_boot_gdt(%ebp)
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/* Disable paging */
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@ -628,7 +631,7 @@ SYM_DATA_START_LOCAL(gdt)
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SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)
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#ifdef CONFIG_EFI_MIXED
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SYM_DATA_LOCAL(efi32_boot_args, .long 0)
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SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0)
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#endif
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/*
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