* [PATCH 1/4] MIPS: traps.c: separate registers print stuff to show_regs()
2015-11-10 7:27 [PATCH 0/4] MIPS: support return from exception; allow user to pass incorrect address to md command Antony Pavlov
@ 2015-11-10 7:27 ` Antony Pavlov
2015-11-10 7:27 ` [PATCH 2/4] MIPS: avoid excessive exception Antony Pavlov
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Antony Pavlov @ 2015-11-10 7:27 UTC (permalink / raw)
To: barebox
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
arch/mips/lib/traps.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/arch/mips/lib/traps.c b/arch/mips/lib/traps.c
index 0a5914e..d69697d 100644
--- a/arch/mips/lib/traps.c
+++ b/arch/mips/lib/traps.c
@@ -96,13 +96,10 @@ static char *get_exc_name(u32 cause)
return "unknown exception";
}
-void barebox_exc_handler(const struct pt_regs *regs)
+static void show_regs(const struct pt_regs *regs)
{
- const int field = 2 * sizeof(unsigned long);
- unsigned int cause = regs->cp0_cause;
int i;
-
- printf("\nOoops, %s!\n\n", get_exc_name(cause));
+ const int field = 2 * sizeof(unsigned long);
/*
* Saved main processor registers
@@ -131,9 +128,17 @@ void barebox_exc_handler(const struct pt_regs *regs)
printf("epc : %0*lx\n", field, regs->cp0_epc);
printf("ra : %0*lx\n", field, regs->regs[31]);
- printf("Status: %08x\n", (uint32_t) regs->cp0_status);
- printf("Cause : %08x\n", cause);
+ printf("Status: %08x\n", (uint32_t)regs->cp0_status);
+ printf("Cause : %08x\n", (uint32_t)regs->cp0_cause);
printf("Config: %08x\n\n", read_c0_config());
+}
+
+void barebox_exc_handler(const struct pt_regs *regs)
+{
+ unsigned int cause = regs->cp0_cause;
+
+ printf("\nOoops, %s!\n\n", get_exc_name(cause));
+ show_regs(regs);
hang();
}
--
2.6.2
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^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 2/4] MIPS: avoid excessive exception
2015-11-10 7:27 [PATCH 0/4] MIPS: support return from exception; allow user to pass incorrect address to md command Antony Pavlov
2015-11-10 7:27 ` [PATCH 1/4] MIPS: traps.c: separate registers print stuff to show_regs() Antony Pavlov
@ 2015-11-10 7:27 ` Antony Pavlov
2015-11-10 7:27 ` [PATCH 3/4] MIPS: import exception registers restoring macros from linux kernel Antony Pavlov
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Antony Pavlov @ 2015-11-10 7:27 UTC (permalink / raw)
To: barebox
This commit clears ERL (ERror Level) flag on start.
If this flag is set then we get 'TLB miss on load or ifetch'
just after return from exception.
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
arch/mips/include/asm/pbl_macros.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/pbl_macros.h b/arch/mips/include/asm/pbl_macros.h
index 681b40a..c4ae6a2 100644
--- a/arch/mips/include/asm/pbl_macros.h
+++ b/arch/mips/include/asm/pbl_macros.h
@@ -145,7 +145,7 @@ copy_loop_exit:
.set push
.set noreorder
mfc0 k0, CP0_STATUS
- li k1, ~ST0_IE
+ li k1, ~(ST0_ERL | ST0_IE)
and k0, k1
mtc0 k0, CP0_STATUS
.set pop
--
2.6.2
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^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 3/4] MIPS: import exception registers restoring macros from linux kernel
2015-11-10 7:27 [PATCH 0/4] MIPS: support return from exception; allow user to pass incorrect address to md command Antony Pavlov
2015-11-10 7:27 ` [PATCH 1/4] MIPS: traps.c: separate registers print stuff to show_regs() Antony Pavlov
2015-11-10 7:27 ` [PATCH 2/4] MIPS: avoid excessive exception Antony Pavlov
@ 2015-11-10 7:27 ` Antony Pavlov
2015-11-10 7:27 ` [PATCH 4/4] MIPS: allow user to pass incorrect address to md command Antony Pavlov
2015-11-11 7:40 ` [PATCH 0/4] MIPS: support return from exception; " Sascha Hauer
4 siblings, 0 replies; 6+ messages in thread
From: Antony Pavlov @ 2015-11-10 7:27 UTC (permalink / raw)
To: barebox
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
arch/mips/include/asm/stackframe.h | 87 ++++++++++++++++++++++++++++++++++++++
1 file changed, 87 insertions(+)
diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 0266ec6..abfa2d2 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -15,6 +15,8 @@
#include <asm/mipsregs.h>
#include <asm/asm-offsets.h>
+#define STATMASK 0x1f
+
.macro SAVE_AT
.set push
.set noat
@@ -102,4 +104,89 @@
SAVE_STATIC
.endm
+ .macro RESTORE_AT
+ .set push
+ .set noat
+ LONG_L $1, PT_R1(sp)
+ .set pop
+ .endm
+
+ .macro RESTORE_TEMP
+ LONG_L $24, PT_LO(sp)
+ mtlo $24
+ LONG_L $24, PT_HI(sp)
+ mthi $24
+#ifdef CONFIG_32BIT
+ LONG_L $8, PT_R8(sp)
+ LONG_L $9, PT_R9(sp)
+#endif
+ LONG_L $10, PT_R10(sp)
+ LONG_L $11, PT_R11(sp)
+ LONG_L $12, PT_R12(sp)
+ LONG_L $13, PT_R13(sp)
+ LONG_L $14, PT_R14(sp)
+ LONG_L $15, PT_R15(sp)
+ LONG_L $24, PT_R24(sp)
+ .endm
+
+ .macro RESTORE_STATIC
+ LONG_L $16, PT_R16(sp)
+ LONG_L $17, PT_R17(sp)
+ LONG_L $18, PT_R18(sp)
+ LONG_L $19, PT_R19(sp)
+ LONG_L $20, PT_R20(sp)
+ LONG_L $21, PT_R21(sp)
+ LONG_L $22, PT_R22(sp)
+ LONG_L $23, PT_R23(sp)
+ LONG_L $30, PT_R30(sp)
+ .endm
+
+ .macro RESTORE_SOME
+ .set push
+ .set reorder
+ .set noat
+ mfc0 a0, CP0_STATUS
+ ori a0, STATMASK
+ xori a0, STATMASK
+ mtc0 a0, CP0_STATUS
+ li v1, 0xff00
+ and a0, v1
+ LONG_L v0, PT_STATUS(sp)
+ nor v1, $0, v1
+ and v0, v1
+ or v0, a0
+ mtc0 v0, CP0_STATUS
+ LONG_L v1, PT_EPC(sp)
+ MTC0 v1, CP0_EPC
+ LONG_L $31, PT_R31(sp)
+ LONG_L $28, PT_R28(sp)
+ LONG_L $25, PT_R25(sp)
+#ifdef CONFIG_64BIT
+ LONG_L $8, PT_R8(sp)
+ LONG_L $9, PT_R9(sp)
+#endif
+ LONG_L $7, PT_R7(sp)
+ LONG_L $6, PT_R6(sp)
+ LONG_L $5, PT_R5(sp)
+ LONG_L $4, PT_R4(sp)
+ LONG_L $3, PT_R3(sp)
+ LONG_L $2, PT_R2(sp)
+ .set pop
+ .endm
+
+ .macro RESTORE_SP_AND_RET
+ LONG_L sp, PT_R29(sp)
+ .set arch=r4000
+ eret
+ .set mips0
+ .endm
+
+ .macro RESTORE_ALL_AND_RET
+ RESTORE_TEMP
+ RESTORE_STATIC
+ RESTORE_AT
+ RESTORE_SOME
+ RESTORE_SP_AND_RET
+ .endm
+
#endif /* _ASM_STACKFRAME_H */
--
2.6.2
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^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 4/4] MIPS: allow user to pass incorrect address to md command
2015-11-10 7:27 [PATCH 0/4] MIPS: support return from exception; allow user to pass incorrect address to md command Antony Pavlov
` (2 preceding siblings ...)
2015-11-10 7:27 ` [PATCH 3/4] MIPS: import exception registers restoring macros from linux kernel Antony Pavlov
@ 2015-11-10 7:27 ` Antony Pavlov
2015-11-11 7:40 ` [PATCH 0/4] MIPS: support return from exception; " Sascha Hauer
4 siblings, 0 replies; 6+ messages in thread
From: Antony Pavlov @ 2015-11-10 7:27 UTC (permalink / raw)
To: barebox
This commit makes it possible to handle exception on
incorrect data access so 'md' command just show 'xxxxxxxx'
instead of crashing the system.
barebox:/ md -l 0xa0000003+4
a0000003: xxxxxxxx ....
Without this commit we will get this
barebox:/ md -l 0xa0000003+4
a0000003:
Ooops, address error on load or ifetch!
...
### ERROR ### Please RESET the board ###
Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
arch/mips/include/asm/barebox.h | 2 +-
arch/mips/lib/genex.S | 6 +++++
arch/mips/lib/traps.c | 52 ++++++++++++++++++++++++++++++++++++-----
3 files changed, 53 insertions(+), 7 deletions(-)
diff --git a/arch/mips/include/asm/barebox.h b/arch/mips/include/asm/barebox.h
index 499b731..e5b964c 100644
--- a/arch/mips/include/asm/barebox.h
+++ b/arch/mips/include/asm/barebox.h
@@ -15,6 +15,6 @@
#ifndef _ASM_MIPS_BAREBOX_H_
#define _ASM_MIPS_BAREBOX_H_
-/* nothing special yet */
+#define ARCH_HAS_DATA_ABORT_MASK
#endif /* _ASM_MIPS_BAREBOX_H_ */
diff --git a/arch/mips/lib/genex.S b/arch/mips/lib/genex.S
index 8941714..5fb2223 100644
--- a/arch/mips/lib/genex.S
+++ b/arch/mips/lib/genex.S
@@ -31,3 +31,9 @@ NESTED(except_vec3_generic, 0, sp)
nop
END(except_vec3_generic)
.set at
+
+FEXPORT(ret_from_exception)
+ .set noat
+ RESTORE_ALL_AND_RET
+ nop
+ .set at
diff --git a/arch/mips/lib/traps.c b/arch/mips/lib/traps.c
index d69697d..5fc32fe 100644
--- a/arch/mips/lib/traps.c
+++ b/arch/mips/lib/traps.c
@@ -1,9 +1,25 @@
#include <common.h>
-
+#include <abort.h>
#include <asm/mipsregs.h>
#include <asm/ptrace.h>
-void barebox_exc_handler(const struct pt_regs *regs);
+static int mips_ignore_data_abort;
+static int mips_data_abort_occurred;
+
+void data_abort_mask(void)
+{
+ mips_data_abort_occurred = 0;
+ mips_ignore_data_abort = 1;
+}
+
+int data_abort_unmask(void)
+{
+ mips_ignore_data_abort = 0;
+
+ return mips_data_abort_occurred != 0;
+}
+
+void barebox_exc_handler(struct pt_regs *regs);
/*
* Trap codes from OpenBSD trap.h
@@ -31,9 +47,14 @@ void barebox_exc_handler(const struct pt_regs *regs);
#define CR_EXC_CODE 0x0000007c
#define CR_EXC_CODE_SHIFT 2
+static inline u32 get_exc_code(u32 cause)
+{
+ return (cause & CR_EXC_CODE) >> CR_EXC_CODE_SHIFT;
+}
+
static char *get_exc_name(u32 cause)
{
- switch ((cause & CR_EXC_CODE) >> CR_EXC_CODE_SHIFT) {
+ switch (get_exc_code(cause)) {
case T_INT:
return "interrupt pending";
@@ -133,12 +154,31 @@ static void show_regs(const struct pt_regs *regs)
printf("Config: %08x\n\n", read_c0_config());
}
-void barebox_exc_handler(const struct pt_regs *regs)
+void barebox_exc_handler(struct pt_regs *regs)
{
unsigned int cause = regs->cp0_cause;
- printf("\nOoops, %s!\n\n", get_exc_name(cause));
- show_regs(regs);
+ if (get_exc_code(cause) == T_ADDR_ERR_LD && mips_ignore_data_abort) {
+
+ mips_data_abort_occurred = 1;
+
+ regs->cp0_epc += 4;
+
+ /*
+ * Don't let your children do this ...
+ */
+ __asm__ __volatile__(
+ "move\t$29, %0\n\t"
+ "j\tret_from_exception"
+ :/* no outputs */
+ :"r" (®s));
+
+ /* Unreached */
+
+ } else {
+ printf("\nOoops, %s!\n\n", get_exc_name(cause));
+ show_regs(regs);
+ }
hang();
}
--
2.6.2
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 0/4] MIPS: support return from exception; allow user to pass incorrect address to md command
2015-11-10 7:27 [PATCH 0/4] MIPS: support return from exception; allow user to pass incorrect address to md command Antony Pavlov
` (3 preceding siblings ...)
2015-11-10 7:27 ` [PATCH 4/4] MIPS: allow user to pass incorrect address to md command Antony Pavlov
@ 2015-11-11 7:40 ` Sascha Hauer
4 siblings, 0 replies; 6+ messages in thread
From: Sascha Hauer @ 2015-11-11 7:40 UTC (permalink / raw)
To: Antony Pavlov; +Cc: barebox
On Tue, Nov 10, 2015 at 10:27:12AM +0300, Antony Pavlov wrote:
> This patchseries adds return from exception for MIPS, so the 'md' command
> incorrect memory accesses can be handled correctly instead of crashing the system,
> e.g.
>
> barebox:/ md -l 0xa0000003+4
> a0000003: xxxxxxxx ....
>
> Without this patchseries we will get this
>
> barebox:/ md -l 0xa0000003+4
> a0000003:
> Ooops, address error on load or ifetch!
>
> ...
>
> ### ERROR ### Please RESET the board ###
>
> The patchseries is tested on QEMU Malta and Black Swift boards.
>
> Antony Pavlov (4):
> MIPS: traps.c: separate registers print stuff to show_regs()
> MIPS: avoid excessive exception
> MIPS: import exception registers restoring macros from linux kernel
> MIPS: allow user to pass incorrect address to md command
Applied, thanks
Sascha
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