efi: stub: use high allocation for converted command line

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>

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 0010c78c4998cf0702299ea2f8a9229e09bb6438..08b1f2f6ea50c186933d0d9e79c82da0b9da4f3f 100644 (file)
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -25,6 +25,8 @@
 #define EFI32_LOADER_SIGNATURE "EL32"
 #define EFI64_LOADER_SIGNATURE "EL64"
 
+#define MAX_CMDLINE_ADDRESS    UINT_MAX
+
 #ifdef CONFIG_X86_32
 
 

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index f07d4a67fa76b3a3cb542e31a24a093c6f7aff97..29ed2f9b218ca9892bfcc72da2d91ba4750f4c97 100644 (file)
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -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;