From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
Matthew Garrett <mjg59@google.com>
Subject: [PATCH 01/20] efi/libstub: fix boot argument handling in mixed mode entry code
Date: Fri, 3 Jan 2020 12:39:34 +0100 [thread overview]
Message-ID: <20200103113953.9571-2-ardb@kernel.org> (raw)
In-Reply-To: <20200103113953.9571-1-ardb@kernel.org>
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>
---
arch/x86/boot/compressed/head_64.S | 17 ++++++++++-------
1 file 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
/*
--
2.20.1
next prev parent reply other threads:[~2020-01-03 11:41 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-03 11:39 [GIT PULL 00/20] More EFI updates for v5.6 Ard Biesheuvel
2020-01-03 11:39 ` Ard Biesheuvel [this message]
2020-01-03 11:39 ` [PATCH 02/20] efi/libstub/x86: force 'hidden' visibility for extern declarations Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 03/20] efi/x86: re-disable RT services for 32-bit kernels running on 64-bit EFI Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 04/20] efi/x86: map the entire EFI vendor string before copying it Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 05/20] efi/x86: avoid redundant cast of EFI firmware service pointer Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 06/20] efi/x86: split off some old memmap handling into separate routines Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 07/20] efi/x86: split SetVirtualAddresMap() wrappers into 32 and 64 bit versions Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 08/20] efi/x86: simplify i386 efi_call_phys() firmware call wrapper Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 09/20] efi/x86: simplify 64-bit EFI " Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 10/20] efi/x86: simplify mixed mode " Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 11/20] efi/x86: drop two near identical versions of efi_runtime_init() Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 12/20] efi/x86: clean up efi_systab_init() routine for legibility Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 13/20] efi/x86: don't panic or BUG() on non-critical error conditions Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 14/20] efi/x86: remove unreachable code in kexec_enter_virtual_mode() Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 15/20] efi/x86: Check number of arguments to variadic functions Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 16/20] efi/x86: Allow translating 64-bit arguments for mixed mode calls Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 17/20] efi: Allow disabling PCI busmastering on bridges during boot Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 18/20] x86/mm: fix NX bit clearing issue in kernel_map_pages_in_pgd Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 19/20] efi/x86: don't map the entire kernel text RW for mixed mode Ard Biesheuvel
2020-01-03 11:39 ` [PATCH 20/20] efi/x86: avoid RWX mappings for all of DRAM Ard Biesheuvel
2020-01-09 9:37 ` [GIT PULL 00/20] More EFI updates for v5.6 Ard Biesheuvel
2020-01-10 18:13 ` Ingo Molnar
2020-01-13 7:29 ` Ard Biesheuvel
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