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efi: stub: use high allocation for converted command line

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Before we can move the command line processing before the allocation
of the kernel, which is required for detecting the 'nokaslr' option
which controls that allocation, move the converted command line higher
up in memory, to prevent it from interfering with the kernel itself.

Since x86 needs the address to fit in 32 bits, use UINT_MAX as the upper
bound there. Otherwise, use ULONG_MAX (i.e., no limit)

Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ard Biesheuvel 2016-01-11 11:47:49 +01:00 committed by Catalin Marinas
parent 2ddbfc81ea
commit 48fcb2d021
2 changed files with 8 additions and 1 deletions
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2
arch/x86/include/asm/efi.h
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@ -25,6 +25,8 @@
#define EFI32_LOADER_SIGNATURE "EL32"
#define EFI64_LOADER_SIGNATURE "EL64"
#define MAX_CMDLINE_ADDRESS UINT_MAX
#ifdef CONFIG_X86_32

7
drivers/firmware/efi/libstub/efi-stub-helper.c
View File

@ -649,6 +649,10 @@ static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
return dst;
}
#ifndef MAX_CMDLINE_ADDRESS
#define MAX_CMDLINE_ADDRESS ULONG_MAX
#endif
/*
* Convert the unicode UEFI command line to ASCII to pass to kernel.
* Size of memory allocated return in *cmd_line_len.
@ -684,7 +688,8 @@ char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
options_bytes++; /* NUL termination */
status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr);
status = efi_high_alloc(sys_table_arg, options_bytes, 0,
&cmdline_addr, MAX_CMDLINE_ADDRESS);
if (status != EFI_SUCCESS)
return NULL;