@@ -25,6 +25,8 @@
#define EFI32_LOADER_SIGNATURE "EL32"
#define EFI64_LOADER_SIGNATURE "EL64"
+#define MAX_CMDLINE_ADDRESS UINT_MAX
+
#ifdef CONFIG_X86_32
@@ -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 +688,15 @@ 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);
+ /*
+ * Allocate a buffer for the converted command line as high up
+ * in memory as is feasible: x86 needs the command line allocation
+ * to be below 4 GB, but non-x86 architectures may not have any
+ * memory there. So prefer below 4 GB, and allocate anywhere if
+ * that fails.
+ */
+ status = efi_high_alloc(sys_table_arg, options_bytes, 0,
+ &cmdline_addr, MAX_CMDLINE_ADDRESS);
if (status != EFI_SUCCESS)
return NULL;
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) Cc: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/x86/include/asm/efi.h | 2 ++ drivers/firmware/efi/libstub/efi-stub-helper.c | 14 +++++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) -- 2.5.0