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[build] Allow assembler section type character to vary by architecture
On some architectures (such as ARM) the "@" character is used as a
comment delimiter.  A section type argument such as "@progbits"
therefore becomes "%progbits".

This is further complicated by the fact that the "%" character has
special meaning for inline assembly when input or output operands are
used, in which cases "@progbits" becomes "%%progbits".

Allow the section type character(s) to be defined via Makefile
variables.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Mar 13, 2016
1 parent a8037ee commit 1f65ed5
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Showing 7 changed files with 29 additions and 8 deletions.
7 changes: 6 additions & 1 deletion src/Makefile.housekeeping
Expand Up @@ -491,6 +491,11 @@ LDFLAGS += -static
#
CFLAGS += -include include/compiler.h

# The section type character (e.g. "@" in "@progbits") varies by
# architecture.
#
CFLAGS += -DASM_TCHAR='$(ASM_TCHAR)' -DASM_TCHAR_OPS='$(ASM_TCHAR_OPS)'

# CFLAGS for specific object types
#
CFLAGS_c +=
Expand Down Expand Up @@ -896,7 +901,7 @@ endif
# Device ID tables (using IDs from ROM definition file)
#
define obj_pci_id_asm
.section ".pci_devlist.$(1)", "a", @progbits
.section ".pci_devlist.$(1)", "a", $(ASM_TCHAR)progbits
.globl pci_devlist_$(1)
pci_devlist_$(1):
.short ( 0x$(1) & 0xffff )
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5 changes: 5 additions & 0 deletions src/arch/x86/Makefile
@@ -1,3 +1,8 @@
# Assembler section type character
#
ASM_TCHAR := @
ASM_TCHAR_OPS := @

# Include common x86 headers
#
INCDIRS += arch/x86/include
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2 changes: 1 addition & 1 deletion src/crypto/certstore.c
Expand Up @@ -45,7 +45,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define CERT( _index, _path ) \
extern char stored_cert_ ## _index ## _data[]; \
extern char stored_cert_ ## _index ## _len[]; \
__asm__ ( ".section \".rodata\", \"a\", @progbits\n\t" \
__asm__ ( ".section \".rodata\", \"a\", " PROGBITS "\n\t" \
"\nstored_cert_" #_index "_data:\n\t" \
".incbin \"" _path "\"\n\t" \
"\nstored_cert_" #_index "_end:\n\t" \
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2 changes: 1 addition & 1 deletion src/crypto/privkey.c
Expand Up @@ -54,7 +54,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/* Raw private key data */
extern char private_key_data[];
extern char private_key_len[];
__asm__ ( ".section \".rodata\", \"a\", @progbits\n\t"
__asm__ ( ".section \".rodata\", \"a\", " PROGBITS "\n\t"
"\nprivate_key_data:\n\t"
#ifdef PRIVATE_KEY
".incbin \"" PRIVATE_KEY "\"\n\t"
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2 changes: 1 addition & 1 deletion src/image/embedded.c
Expand Up @@ -18,7 +18,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define EMBED( _index, _path, _name ) \
extern char embedded_image_ ## _index ## _data[]; \
extern char embedded_image_ ## _index ## _len[]; \
__asm__ ( ".section \".rodata\", \"a\", @progbits\n\t" \
__asm__ ( ".section \".rodata\", \"a\", " PROGBITS "\n\t" \
"\nembedded_image_" #_index "_data:\n\t" \
".incbin \"" _path "\"\n\t" \
"\nembedded_image_" #_index "_end:\n\t" \
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17 changes: 14 additions & 3 deletions src/include/compiler.h
Expand Up @@ -52,6 +52,17 @@
/** Stringify expanded argument */
#define _S2( x ) _S1 ( x )

/* Assembler section types */
#ifdef ASSEMBLY
#define PROGBITS _C2 ( ASM_TCHAR, progbits )
#define NOBITS _C2 ( ASM_TCHAR, nobits )
#else
#define PROGBITS_OPS _S2 ( ASM_TCHAR_OPS ) "progbits"
#define PROGBITS _S2 ( ASM_TCHAR ) "progbits"
#define NOBITS_OPS _S2 ( ASM_TCHAR_OPS ) "nobits"
#define NOBITS _S2 ( ASM_TCHAR ) "nobits"
#endif

/**
* @defgroup symmacros Macros to provide or require explicit symbols
* @{
Expand All @@ -64,7 +75,7 @@
*/
#ifdef ASSEMBLY
#define PROVIDE_SYMBOL( symbol ) \
.section ".provided", "a", @nobits ; \
.section ".provided", "a", NOBITS ; \
.hidden symbol ; \
.globl symbol ; \
symbol: ; \
Expand Down Expand Up @@ -139,14 +150,14 @@
*/
#ifdef ASSEMBLY
#define PROVIDE_REQUIRING_SYMBOL() \
.section ".tbl.requiring_symbols", "a", @progbits ; \
.section ".tbl.requiring_symbols", "a", PROGBITS ; \
__requiring_symbol__: .byte 0 ; \
.size __requiring_symbol__, . - __requiring_symbol__ ; \
.previous
#else
#define PROVIDE_REQUIRING_SYMBOL() \
__asm__ ( ".section \".tbl.requiring_symbols\", " \
" \"a\", @progbits\n" \
" \"a\", " PROGBITS "\n" \
"__requiring_symbol__:\t.byte 0\n" \
".size __requiring_symbol__, " \
" . - __requiring_symbol__\n" \
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2 changes: 1 addition & 1 deletion src/include/errno.h
Expand Up @@ -258,7 +258,7 @@ static inline void eplatform_discard ( int dummy __unused, ... ) {}
* @ret error Error
*/
#define __einfo_error( einfo ) ( { \
__asm__ ( ".section \".einfo\", \"\", @progbits\n\t" \
__asm__ ( ".section \".einfo\", \"\", " PROGBITS_OPS "\n\t" \
".align 8\n\t" \
"\n1:\n\t" \
".long ( 4f - 1b )\n\t" \
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