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authorLinus Torvalds <torvalds@linux-foundation.org>2014-01-30 18:13:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-30 18:13:20 -0800
commit10ffe3dbf7f9c63d6fde3d1fe23b8fd2ae4d7bd1 (patch)
tree579d5f88d8cb9eea77925a516fdaede366f05d82 /arch/x86
parentf8a504c404c6c4abbed4ae34fe1027ba3c24d035 (diff)
parentde3accdaec88851874c573031de007283e90b199 (diff)
Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build bits from Peter Anvin: "Various build-related minor bits. Most of this is work by David Woodhouse to be able to compile the early boot code with clang/llvm; we have also managed to push an actual -m16 option into gcc 4.9 so this makes us use that option if available instead of hacking it. The balance is a patch from Michael Davidson to the relocs program to help manual debugging. None of these should change the actual compiled binary with currently released compilers" * 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, build: Build 16-bit code with -m16 where possible x86, boot: Fix word-size assumptions in has_eflag() inline asm x86, boot: Use __attribute__((used)) to ensure videocard structs are emitted x86: Remove duplication of 16-bit CFLAGS x86, relocs: Add manual debug mode
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/Makefile22
-rw-r--r--arch/x86/boot/Makefile15
-rw-r--r--arch/x86/boot/cpuflags.c25
-rw-r--r--arch/x86/boot/video.h2
-rw-r--r--arch/x86/realmode/rm/Makefile17
-rw-r--r--arch/x86/tools/relocs.c30
-rw-r--r--arch/x86/tools/relocs.h7
-rw-r--r--arch/x86/tools/relocs_common.c16
8 files changed, 91 insertions, 43 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 13b22e0f681..eeda43abed6 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -11,6 +11,28 @@ else
KBUILD_DEFCONFIG := $(ARCH)_defconfig
endif
+# How to compile the 16-bit code. Note we always compile for -march=i386;
+# that way we can complain to the user if the CPU is insufficient.
+#
+# The -m16 option is supported by GCC >= 4.9 and clang >= 3.5. For
+# older versions of GCC, we need to play evil and unreliable tricks to
+# attempt to ensure that our asm(".code16gcc") is first in the asm
+# output.
+CODE16GCC_CFLAGS := -m32 -include $(srctree)/arch/x86/boot/code16gcc.h \
+ $(call cc-option, -fno-toplevel-reorder,\
+ $(call cc-option, -fno-unit-at-a-time))
+M16_CFLAGS := $(call cc-option, -m16, $(CODE16GCC_CFLAGS))
+
+REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \
+ -DDISABLE_BRANCH_PROFILING \
+ -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
+ -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
+ -mno-mmx -mno-sse \
+ $(call cc-option, -ffreestanding) \
+ $(call cc-option, -fno-stack-protector) \
+ $(call cc-option, -mpreferred-stack-boundary=2)
+export REALMODE_CFLAGS
+
# BITS is used as extension for files which are available in a 32 bit
# and a 64 bit version to simplify shared Makefiles.
# e.g.: obj-y += foo_$(BITS).o
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index de706691800..878df7e88cd 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -51,20 +51,7 @@ $(obj)/cpustr.h: $(obj)/mkcpustr FORCE
# ---------------------------------------------------------------------------
-# How to compile the 16-bit code. Note we always compile for -march=i386,
-# that way we can complain to the user if the CPU is insufficient.
-KBUILD_CFLAGS := $(USERINCLUDE) -m32 -g -Os -D_SETUP -D__KERNEL__ \
- -DDISABLE_BRANCH_PROFILING \
- -Wall -Wstrict-prototypes \
- -march=i386 -mregparm=3 \
- -include $(srctree)/$(src)/code16gcc.h \
- -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
- -mno-mmx -mno-sse \
- $(call cc-option, -ffreestanding) \
- $(call cc-option, -fno-toplevel-reorder,\
- $(call cc-option, -fno-unit-at-a-time)) \
- $(call cc-option, -fno-stack-protector) \
- $(call cc-option, -mpreferred-stack-boundary=2)
+KBUILD_CFLAGS := $(USERINCLUDE) $(REALMODE_CFLAGS) -D_SETUP
KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
GCOV_PROFILE := n
diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c
index a9fcb7cfb24..431fa5f8453 100644
--- a/arch/x86/boot/cpuflags.c
+++ b/arch/x86/boot/cpuflags.c
@@ -28,20 +28,35 @@ static int has_fpu(void)
return fsw == 0 && (fcw & 0x103f) == 0x003f;
}
+/*
+ * For building the 16-bit code we want to explicitly specify 32-bit
+ * push/pop operations, rather than just saying 'pushf' or 'popf' and
+ * letting the compiler choose. But this is also included from the
+ * compressed/ directory where it may be 64-bit code, and thus needs
+ * to be 'pushfq' or 'popfq' in that case.
+ */
+#ifdef __x86_64__
+#define PUSHF "pushfq"
+#define POPF "popfq"
+#else
+#define PUSHF "pushfl"
+#define POPF "popfl"
+#endif
+
int has_eflag(unsigned long mask)
{
unsigned long f0, f1;
- asm volatile("pushf \n\t"
- "pushf \n\t"
+ asm volatile(PUSHF " \n\t"
+ PUSHF " \n\t"
"pop %0 \n\t"
"mov %0,%1 \n\t"
"xor %2,%1 \n\t"
"push %1 \n\t"
- "popf \n\t"
- "pushf \n\t"
+ POPF " \n\t"
+ PUSHF " \n\t"
"pop %1 \n\t"
- "popf"
+ POPF
: "=&r" (f0), "=&r" (f1)
: "ri" (mask));
diff --git a/arch/x86/boot/video.h b/arch/x86/boot/video.h
index ff339c5db31..0bb25491262 100644
--- a/arch/x86/boot/video.h
+++ b/arch/x86/boot/video.h
@@ -80,7 +80,7 @@ struct card_info {
u16 xmode_n; /* Size of unprobed mode range */
};
-#define __videocard struct card_info __attribute__((section(".videocards")))
+#define __videocard struct card_info __attribute__((used,section(".videocards")))
extern struct card_info video_cards[], video_cards_end[];
int mode_defined(u16 mode); /* video.c */
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 9cac82588cb..3497f14e4de 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -64,20 +64,7 @@ $(obj)/realmode.relocs: $(obj)/realmode.elf FORCE
# ---------------------------------------------------------------------------
-# How to compile the 16-bit code. Note we always compile for -march=i386,
-# that way we can complain to the user if the CPU is insufficient.
-KBUILD_CFLAGS := $(LINUXINCLUDE) -m32 -g -Os -D_SETUP -D__KERNEL__ -D_WAKEUP \
- -I$(srctree)/arch/x86/boot \
- -DDISABLE_BRANCH_PROFILING \
- -Wall -Wstrict-prototypes \
- -march=i386 -mregparm=3 \
- -include $(srctree)/$(src)/../../boot/code16gcc.h \
- -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
- -mno-mmx -mno-sse \
- $(call cc-option, -ffreestanding) \
- $(call cc-option, -fno-toplevel-reorder,\
- $(call cc-option, -fno-unit-at-a-time)) \
- $(call cc-option, -fno-stack-protector) \
- $(call cc-option, -mpreferred-stack-boundary=2)
+KBUILD_CFLAGS := $(LINUXINCLUDE) $(REALMODE_CFLAGS) -D_SETUP -D_WAKEUP \
+ -I$(srctree)/arch/x86/boot
KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
GCOV_PROFILE := n
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 11f9285a2ff..cfbdbdb4e17 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -1025,6 +1025,29 @@ static void emit_relocs(int as_text, int use_real_mode)
}
}
+/*
+ * As an aid to debugging problems with different linkers
+ * print summary information about the relocs.
+ * Since different linkers tend to emit the sections in
+ * different orders we use the section names in the output.
+ */
+static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
+ const char *symname)
+{
+ printf("%s\t%s\t%s\t%s\n",
+ sec_name(sec->shdr.sh_info),
+ rel_type(ELF_R_TYPE(rel->r_info)),
+ symname,
+ sec_name(sym->st_shndx));
+ return 0;
+}
+
+static void print_reloc_info(void)
+{
+ printf("reloc section\treloc type\tsymbol\tsymbol section\n");
+ walk_relocs(do_reloc_info);
+}
+
#if ELF_BITS == 64
# define process process_64
#else
@@ -1032,7 +1055,8 @@ static void emit_relocs(int as_text, int use_real_mode)
#endif
void process(FILE *fp, int use_real_mode, int as_text,
- int show_absolute_syms, int show_absolute_relocs)
+ int show_absolute_syms, int show_absolute_relocs,
+ int show_reloc_info)
{
regex_init(use_real_mode);
read_ehdr(fp);
@@ -1050,5 +1074,9 @@ void process(FILE *fp, int use_real_mode, int as_text,
print_absolute_relocs();
return;
}
+ if (show_reloc_info) {
+ print_reloc_info();
+ return;
+ }
emit_relocs(as_text, use_real_mode);
}
diff --git a/arch/x86/tools/relocs.h b/arch/x86/tools/relocs.h
index 07cdb1eca4f..f59590645b6 100644
--- a/arch/x86/tools/relocs.h
+++ b/arch/x86/tools/relocs.h
@@ -29,8 +29,9 @@ enum symtype {
};
void process_32(FILE *fp, int use_real_mode, int as_text,
- int show_absolute_syms, int show_absolute_relocs);
+ int show_absolute_syms, int show_absolute_relocs,
+ int show_reloc_info);
void process_64(FILE *fp, int use_real_mode, int as_text,
- int show_absolute_syms, int show_absolute_relocs);
-
+ int show_absolute_syms, int show_absolute_relocs,
+ int show_reloc_info);
#endif /* RELOCS_H */
diff --git a/arch/x86/tools/relocs_common.c b/arch/x86/tools/relocs_common.c
index 44d396823a5..acab636bcb3 100644
--- a/arch/x86/tools/relocs_common.c
+++ b/arch/x86/tools/relocs_common.c
@@ -11,12 +11,13 @@ void die(char *fmt, ...)
static void usage(void)
{
- die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
+ die("relocs [--abs-syms|--abs-relocs|--reloc-info|--text|--realmode]" \
+ " vmlinux\n");
}
int main(int argc, char **argv)
{
- int show_absolute_syms, show_absolute_relocs;
+ int show_absolute_syms, show_absolute_relocs, show_reloc_info;
int as_text, use_real_mode;
const char *fname;
FILE *fp;
@@ -25,6 +26,7 @@ int main(int argc, char **argv)
show_absolute_syms = 0;
show_absolute_relocs = 0;
+ show_reloc_info = 0;
as_text = 0;
use_real_mode = 0;
fname = NULL;
@@ -39,6 +41,10 @@ int main(int argc, char **argv)
show_absolute_relocs = 1;
continue;
}
+ if (strcmp(arg, "--reloc-info") == 0) {
+ show_reloc_info = 1;
+ continue;
+ }
if (strcmp(arg, "--text") == 0) {
as_text = 1;
continue;
@@ -67,10 +73,12 @@ int main(int argc, char **argv)
rewind(fp);
if (e_ident[EI_CLASS] == ELFCLASS64)
process_64(fp, use_real_mode, as_text,
- show_absolute_syms, show_absolute_relocs);
+ show_absolute_syms, show_absolute_relocs,
+ show_reloc_info);
else
process_32(fp, use_real_mode, as_text,
- show_absolute_syms, show_absolute_relocs);
+ show_absolute_syms, show_absolute_relocs,
+ show_reloc_info);
fclose(fp);
return 0;
}