2023-09-15 21:46:57

by Ard Biesheuvel

[permalink] [raw]
Subject: [PATCH v3 2/8] x86/boot: Set EFI handover offset directly in header asm

From: Ard Biesheuvel <[email protected]>

The offsets of the EFI handover entrypoints are available to the
assembler when constructing the header, so there is no need to set them
from the build tool afterwards.

This change has no impact on the resulting bzImage binary.

Signed-off-by: Ard Biesheuvel <[email protected]>
---
arch/x86/boot/header.S | 18 ++++++++++++++-
arch/x86/boot/tools/build.c | 24 --------------------
2 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 5575d0f06bab..72744ba440f6 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -524,8 +524,24 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
# define INIT_SIZE VO_INIT_SIZE
#endif

+ .macro __handover_offset
+#ifndef CONFIG_EFI_HANDOVER_PROTOCOL
+ .long 0
+#elif !defined(CONFIG_X86_64)
+ .long ZO_efi32_stub_entry
+#else
+ /* Yes, this is really how we defined it :( */
+ .long ZO_efi64_stub_entry - 0x200
+#ifdef CONFIG_EFI_MIXED
+ .if ZO_efi32_stub_entry != ZO_efi64_stub_entry - 0x200
+ .error "32-bit and 64-bit EFI entry points do not match"
+ .endif
+#endif
+#endif
+ .endm
+
init_size: .long INIT_SIZE # kernel initialization size
-handover_offset: .long 0 # Filled in by build.c
+handover_offset: __handover_offset
kernel_info_offset: .long ZO_kernel_info

# End of setup header #####################################################
diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index 14ef13fe7ab0..069497543164 100644
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -55,8 +55,6 @@ u8 buf[SETUP_SECT_MAX*512];
#define PECOFF_COMPAT_RESERVE 0x0
#endif

-static unsigned long efi32_stub_entry;
-static unsigned long efi64_stub_entry;
static unsigned long efi_pe_entry;
static unsigned long efi32_pe_entry;
static unsigned long _end;
@@ -265,31 +263,12 @@ static void efi_stub_defaults(void)
#endif
}

-static void efi_stub_entry_update(void)
-{
- unsigned long addr = efi32_stub_entry;
-
-#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
-#ifdef CONFIG_X86_64
- /* Yes, this is really how we defined it :( */
- addr = efi64_stub_entry - 0x200;
-#endif
-
-#ifdef CONFIG_EFI_MIXED
- if (efi32_stub_entry != addr)
- die("32-bit and 64-bit EFI entry points do not match\n");
-#endif
-#endif
- put_unaligned_le32(addr, &buf[0x264]);
-}
-
#else

static inline void update_pecoff_setup_and_reloc(unsigned int size) {}
static inline void update_pecoff_text(unsigned int text_start,
unsigned int file_sz) {}
static inline void efi_stub_defaults(void) {}
-static inline void efi_stub_entry_update(void) {}

static inline int reserve_pecoff_reloc_section(int c)
{
@@ -332,8 +311,6 @@ static void parse_zoffset(char *fname)
p = (char *)buf;

while (p && *p) {
- PARSE_ZOFS(p, efi32_stub_entry);
- PARSE_ZOFS(p, efi64_stub_entry);
PARSE_ZOFS(p, efi_pe_entry);
PARSE_ZOFS(p, efi32_pe_entry);
PARSE_ZOFS(p, _end);
@@ -416,7 +393,6 @@ int main(int argc, char ** argv)

update_pecoff_text(setup_sectors * 512, i + (sys_size * 16));

- efi_stub_entry_update();

crc = partial_crc32(buf, i, crc);
if (fwrite(buf, 1, i, dest) != i)
--
2.42.0.459.ge4e396fd5e-goog


Subject: [tip: x86/boot] x86/boot: Set EFI handover offset directly in header asm

The following commit has been merged into the x86/boot branch of tip:

Commit-ID: eac956345f99dda3d68f4ae6cf7b494105e54780
Gitweb: https://git.kernel.org/tip/eac956345f99dda3d68f4ae6cf7b494105e54780
Author: Ard Biesheuvel <[email protected]>
AuthorDate: Fri, 15 Sep 2023 17:16:26
Committer: Ingo Molnar <[email protected]>
CommitterDate: Sun, 17 Sep 2023 19:48:42 +02:00

x86/boot: Set EFI handover offset directly in header asm

The offsets of the EFI handover entrypoints are available to the
assembler when constructing the header, so there is no need to set them
from the build tool afterwards.

This change has no impact on the resulting bzImage binary.

Signed-off-by: Ard Biesheuvel <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/boot/header.S | 18 +++++++++++++++++-
arch/x86/boot/tools/build.c | 24 ------------------------
2 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 5575d0f..72744ba 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -524,8 +524,24 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
# define INIT_SIZE VO_INIT_SIZE
#endif

+ .macro __handover_offset
+#ifndef CONFIG_EFI_HANDOVER_PROTOCOL
+ .long 0
+#elif !defined(CONFIG_X86_64)
+ .long ZO_efi32_stub_entry
+#else
+ /* Yes, this is really how we defined it :( */
+ .long ZO_efi64_stub_entry - 0x200
+#ifdef CONFIG_EFI_MIXED
+ .if ZO_efi32_stub_entry != ZO_efi64_stub_entry - 0x200
+ .error "32-bit and 64-bit EFI entry points do not match"
+ .endif
+#endif
+#endif
+ .endm
+
init_size: .long INIT_SIZE # kernel initialization size
-handover_offset: .long 0 # Filled in by build.c
+handover_offset: __handover_offset
kernel_info_offset: .long ZO_kernel_info

# End of setup header #####################################################
diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index 14ef13f..0694975 100644
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -55,8 +55,6 @@ u8 buf[SETUP_SECT_MAX*512];
#define PECOFF_COMPAT_RESERVE 0x0
#endif

-static unsigned long efi32_stub_entry;
-static unsigned long efi64_stub_entry;
static unsigned long efi_pe_entry;
static unsigned long efi32_pe_entry;
static unsigned long _end;
@@ -265,31 +263,12 @@ static void efi_stub_defaults(void)
#endif
}

-static void efi_stub_entry_update(void)
-{
- unsigned long addr = efi32_stub_entry;
-
-#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
-#ifdef CONFIG_X86_64
- /* Yes, this is really how we defined it :( */
- addr = efi64_stub_entry - 0x200;
-#endif
-
-#ifdef CONFIG_EFI_MIXED
- if (efi32_stub_entry != addr)
- die("32-bit and 64-bit EFI entry points do not match\n");
-#endif
-#endif
- put_unaligned_le32(addr, &buf[0x264]);
-}
-
#else

static inline void update_pecoff_setup_and_reloc(unsigned int size) {}
static inline void update_pecoff_text(unsigned int text_start,
unsigned int file_sz) {}
static inline void efi_stub_defaults(void) {}
-static inline void efi_stub_entry_update(void) {}

static inline int reserve_pecoff_reloc_section(int c)
{
@@ -332,8 +311,6 @@ static void parse_zoffset(char *fname)
p = (char *)buf;

while (p && *p) {
- PARSE_ZOFS(p, efi32_stub_entry);
- PARSE_ZOFS(p, efi64_stub_entry);
PARSE_ZOFS(p, efi_pe_entry);
PARSE_ZOFS(p, efi32_pe_entry);
PARSE_ZOFS(p, _end);
@@ -416,7 +393,6 @@ int main(int argc, char ** argv)

update_pecoff_text(setup_sectors * 512, i + (sys_size * 16));

- efi_stub_entry_update();

crc = partial_crc32(buf, i, crc);
if (fwrite(buf, 1, i, dest) != i)