Le 27/11/2020 à 04:02, Jordan Niethe a écrit :
This enables GENERIC_BUG_RELATIVE_POINTERS on Power so that 32-bit
offsets are stored in the bug entries rather than 64-bit pointers.
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
---
arch/powerpc/Kconfig | 4 ++++
arch/powerpc/include/asm/bug.h | 37 ++++++++++++++++++++++++++++++++--
arch/powerpc/xmon/xmon.c | 17 ++++++++++++++--
3 files changed, 54 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e9f13fe08492..294108e0e5c6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -311,6 +311,10 @@ config GENERIC_BUG
default y
depends on BUG
+config GENERIC_BUG_RELATIVE_POINTERS
+ def_bool y
+ depends on GENERIC_BUG
+
config SYS_SUPPORTS_APM_EMULATION
default y if PMAC_APM_EMU
bool
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 338f36cd9934..d03d834042a1 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -12,7 +12,11 @@
#ifdef CONFIG_DEBUG_BUGVERBOSE
.macro EMIT_BUG_ENTRY addr,file,line,flags
.section __bug_table,"aw"
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
As far as I understand, as soon as CONFIG_BUG is selected, GENERIC_BUG is automatically selected so
GENERIC_BUG_RELATIVE_POINTERS is selected as well. Therefore this #ifndef is never possible.
5001: PPC_LONG \addr, 5002f
+#else
+5001: .4byte \addr - 5001b, 5002f - 5001b
+#endif /* CONFIG_GENERIC_BUG_RELATIVE_POINTERS */
.short \line, \flags
.org 5001b+BUG_ENTRY_SIZE
.previous
@@ -23,7 +27,11 @@
#else
.macro EMIT_BUG_ENTRY addr,file,line,flags
.section __bug_table,"aw"
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
Same
5001: PPC_LONG \addr
+#else
+5001: .4byte \addr - 5001b
+#endif /* CONFIG_GENERIC_BUG_RELATIVE_POINTERS */
.short \flags
.org 5001b+BUG_ENTRY_SIZE
.previous
@@ -34,20 +42,45 @@
/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
sizeof(struct bug_entry), respectively */
#ifdef CONFIG_DEBUG_BUGVERBOSE
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
Same
#define _EMIT_BUG_ENTRY \
".section __bug_table,\"aw\"\n" \
"2:\t" PPC_LONG "1b, %0\n" \
"\t.short %1, %2\n" \
".org 2b+%3\n" \
".previous\n"
-#else
+
+#else /* relative pointers */
+
+#define _EMIT_BUG_ENTRY \
+ ".section __bug_table,\"aw\"\n" \
+ "2:\t.4byte 1b - 2b, %0 - 2b\n" \
+ "\t.short %1, %2\n" \
+ ".org 2b+%3\n" \
+ ".previous\n"
+#endif /* relative pointers */
+
+#else /* verbose */
+
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
Same
#define _EMIT_BUG_ENTRY \
".section __bug_table,\"aw\"\n" \
"2:\t" PPC_LONG "1b\n" \
"\t.short %2\n" \
".org 2b+%3\n" \
".previous\n"
-#endif
+
+#else /* relative pointers */
+
+#define _EMIT_BUG_ENTRY \
+ ".section __bug_table,\"aw\"\n" \
+ "2:\t.4byte 1b - 2b\n" \
+ "\t.short %2\n" \
+ ".org 2b+%3\n" \
+ ".previous\n"
+
+#endif /* relative pointers */
+#endif /* verbose */
#define BUG_ENTRY(insn, flags, ...) \
__asm__ __volatile__( \
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 55c43a6c9111..5f7cf7e95767 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1731,6 +1731,9 @@ static void print_bug_trap(struct pt_regs *regs)
#ifdef CONFIG_BUG
const struct bug_entry *bug;
unsigned long addr;
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+ char *file;
+#endif
if (regs->msr & MSR_PR)
return; /* not in kernel */
@@ -1744,10 +1747,20 @@ static void print_bug_trap(struct pt_regs *regs)
return;
#ifdef CONFIG_DEBUG_BUGVERBOSE
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
Same
+ file = bug->file;
+#else /* relative pointers */
+ file = (char *)bug + bug->file_disp;
+#endif /* relative pointers */
printf("kernel BUG at %s:%u!\n",
- bug->file, bug->line);
+ file, bug->line);
#else
- printf("kernel BUG at %px!\n", (void *)bug->bug_addr);
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
Same
+ addr = bug->addr;
+#else /* relative pointers */
+ addr = (unsigned long)bug + bug->bug_addr_disp;
+#endif /* relative pointers */
+ printf("kernel BUG at %px!\n", (void *)addr);
#endif
#endif /* CONFIG_BUG */
}
Christophe
