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Subject[PATCH v3 02/29] x86_32: boot, extract efi_pe_entry from startup_32
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efi_pe_entry body is somehow squashed into startup_32. In the old days,
we forced startup_32 to start at offset 0x00 and efi_pe_entry to start
at 0x10. But this requirement was removed in 99f857db8857 ("x86, build:
Dynamically find entry points in compressed startup code") long time
ago.

The way it is now makes the code less readable and illogical. And given
we can now safely extract the inlined efi_pe_entry body from
startup_32 into a separate function, we do so and we separate it to two
functions as they are marked already: efi_pe_entry + efi32_stub_entry.

We also annotate the functions appropriatelly by ENTRY+ENDPROC.

ABI offset is preserved:
0000 128 FUNC GLOBAL DEFAULT 6 startup_32
0080 60 FUNC GLOBAL DEFAULT 6 efi_pe_entry
00bc 68 FUNC GLOBAL DEFAULT 6 efi32_stub_entry

On the top-level, it looked like:
ENTRY(startup_32)
#ifdef CONFIG_EFI_STUB ; start of inlined
jmp preferred_addr
ENTRY(efi_pe_entry)
... ; a lot of assembly (efi_pe_entry)
ENTRY(efi32_stub_entry)
... ; a lot of assembly (efi32_stub_entry)
leal preferred_addr(%eax), %eax
jmp *%eax
preferred_addr:
#endif ; end of inlined
... ; a lot of assembly (startup_32)
ENDPROC(startup_32)

And it is converted into:
ENTRY(startup_32)
... ; a lot of assembly (startup_32)
ENDPROC(startup_32)

#ifdef CONFIG_EFI_STUB
ENTRY(efi_pe_entry)
... ; a lot of assembly (efi_pe_entry)
ENDPROC(efi_pe_entry)

ENTRY(efi32_stub_entry)
... ; a lot of assembly (efi32_stub_entry)
leal startup_32(%eax), %eax
jmp *%eax
ENDPROC(efi32_stub_entry)
#endif

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <x86@kernel.org>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
---
arch/x86/boot/compressed/head_32.S | 129 ++++++++++++++++++-------------------
1 file changed, 64 insertions(+), 65 deletions(-)

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index d85b9625e836..11c68cf53d4e 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -61,71 +61,6 @@

__HEAD
ENTRY(startup_32)
-#ifdef CONFIG_EFI_STUB
- jmp preferred_addr
-
- /*
- * We don't need the return address, so set up the stack so
- * efi_main() can find its arguments.
- */
-ENTRY(efi_pe_entry)
- add $0x4, %esp
-
- call 1f
-1: popl %esi
- subl $1b, %esi
-
- popl %ecx
- movl %ecx, efi32_config(%esi) /* Handle */
- popl %ecx
- movl %ecx, efi32_config+8(%esi) /* EFI System table pointer */
-
- /* Relocate efi_config->call() */
- leal efi32_config(%esi), %eax
- add %esi, 40(%eax)
- pushl %eax
-
- call make_boot_params
- cmpl $0, %eax
- je fail
- movl %esi, BP_code32_start(%eax)
- popl %ecx
- pushl %eax
- pushl %ecx
- jmp 2f /* Skip efi_config initialization */
-
-ENTRY(efi32_stub_entry)
- add $0x4, %esp
- popl %ecx
- popl %edx
-
- call 1f
-1: popl %esi
- subl $1b, %esi
-
- movl %ecx, efi32_config(%esi) /* Handle */
- movl %edx, efi32_config+8(%esi) /* EFI System table pointer */
-
- /* Relocate efi_config->call() */
- leal efi32_config(%esi), %eax
- add %esi, 40(%eax)
- pushl %eax
-2:
- call efi_main
- cmpl $0, %eax
- movl %eax, %esi
- jne 2f
-fail:
- /* EFI init failed, so hang. */
- hlt
- jmp fail
-2:
- movl BP_code32_start(%esi), %eax
- leal preferred_addr(%eax), %eax
- jmp *%eax
-
-preferred_addr:
-#endif
cld
/*
* Test KEEP_SEGMENTS flag to see if the bootloader is asking
@@ -208,6 +143,70 @@ preferred_addr:
jmp *%eax
ENDPROC(startup_32)

+#ifdef CONFIG_EFI_STUB
+/*
+ * We don't need the return address, so set up the stack so efi_main() can find
+ * its arguments.
+ */
+ENTRY(efi_pe_entry)
+ add $0x4, %esp
+
+ call 1f
+1: popl %esi
+ subl $1b, %esi
+
+ popl %ecx
+ movl %ecx, efi32_config(%esi) /* Handle */
+ popl %ecx
+ movl %ecx, efi32_config+8(%esi) /* EFI System table pointer */
+
+ /* Relocate efi_config->call() */
+ leal efi32_config(%esi), %eax
+ add %esi, 40(%eax)
+ pushl %eax
+
+ call make_boot_params
+ cmpl $0, %eax
+ je fail
+ movl %esi, BP_code32_start(%eax)
+ popl %ecx
+ pushl %eax
+ pushl %ecx
+ jmp 2f /* Skip efi_config initialization */
+ENDPROC(efi_pe_entry)
+
+ENTRY(efi32_stub_entry)
+ add $0x4, %esp
+ popl %ecx
+ popl %edx
+
+ call 1f
+1: popl %esi
+ subl $1b, %esi
+
+ movl %ecx, efi32_config(%esi) /* Handle */
+ movl %edx, efi32_config+8(%esi) /* EFI System table pointer */
+
+ /* Relocate efi_config->call() */
+ leal efi32_config(%esi), %eax
+ add %esi, 40(%eax)
+ pushl %eax
+2:
+ call efi_main
+ cmpl $0, %eax
+ movl %eax, %esi
+ jne 2f
+fail:
+ /* EFI init failed, so hang. */
+ hlt
+ jmp fail
+2:
+ movl BP_code32_start(%esi), %eax
+ leal startup_32(%eax), %eax
+ jmp *%eax
+ENDPROC(efi32_stub_entry)
+#endif
+
.text
relocated:

--
2.12.2
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