* [PATCH v5 0/3] RISC-V: three fixup and cleanups
@ 2022-07-01 12:05 Xianting Tian
2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw)
To: palmer; +Cc: guoren, linux-kernel, linux-riscv
Hi Palmer,
These 3 patches are some obviously fixup and cleanups, please have a look, thanks.
Xianting Tian (2):
RISC-V: use __smp_processor_id() instead of smp_processor_id()
RISC-V: Fixup fast call of crash_kexec()
Guo Ren (1):
riscv: atomic: Clean up unnecessary acquire and release definitions
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^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id()
2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian
@ 2022-07-01 12:05 ` Xianting Tian
2022-07-01 12:05 ` [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec() Xianting Tian
2022-07-01 12:05 ` [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions Xianting Tian
2 siblings, 0 replies; 5+ messages in thread
From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw)
To: palmer; +Cc: guoren, linux-kernel, linux-riscv, Xianting Tian
Use __smp_processor_id() to avoid check the preemption context when
CONFIG_DEBUG_PREEMPT enabled, as we will enter crash kernel and no
return.
Without the patch,
[ 103.781044] sysrq: Trigger a crash
[ 103.784625] Kernel panic - not syncing: sysrq triggered crash
[ 103.837634] CPU1: off
[ 103.889668] CPU2: off
[ 103.933479] CPU3: off
[ 103.939424] Starting crashdump kernel...
[ 103.943442] BUG: using smp_processor_id() in preemptible [00000000] code: sh/346
[ 103.950884] caller is debug_smp_processor_id+0x1c/0x26
[ 103.956051] CPU: 0 PID: 346 Comm: sh Kdump: loaded Not tainted 5.10.113-00002-gce03f03bf4ec-dirty #149
[ 103.965355] Call Trace:
[ 103.967805] [<ffffffe00020372a>] walk_stackframe+0x0/0xa2
[ 103.973206] [<ffffffe000bcf1f4>] show_stack+0x32/0x3e
[ 103.978258] [<ffffffe000bd382a>] dump_stack_lvl+0x72/0x8e
[ 103.983655] [<ffffffe000bd385a>] dump_stack+0x14/0x1c
[ 103.988705] [<ffffffe000bdc8fe>] check_preemption_disabled+0x9e/0xaa
[ 103.995057] [<ffffffe000bdc926>] debug_smp_processor_id+0x1c/0x26
[ 104.001150] [<ffffffe000206c64>] machine_kexec+0x22/0xd0
[ 104.006463] [<ffffffe000291a7e>] __crash_kexec+0x6a/0xa4
[ 104.011774] [<ffffffe000bcf3fa>] panic+0xfc/0x2b0
[ 104.016480] [<ffffffe000656ca4>] sysrq_reset_seq_param_set+0x0/0x70
[ 104.022745] [<ffffffe000657310>] __handle_sysrq+0x8c/0x154
[ 104.028229] [<ffffffe0006577e8>] write_sysrq_trigger+0x5a/0x6a
[ 104.034061] [<ffffffe0003d90e0>] proc_reg_write+0x58/0xd4
[ 104.039459] [<ffffffe00036cff4>] vfs_write+0x7e/0x254
[ 104.044509] [<ffffffe00036d2f6>] ksys_write+0x58/0xbe
[ 104.049558] [<ffffffe00036d36a>] sys_write+0xe/0x16
[ 104.054434] [<ffffffe000201b9a>] ret_from_syscall+0x0/0x2
[ 104.067863] Will call new kernel at ecc00000 from hart id 0
[ 104.074939] FDT image at fc5ee000
[ 104.079523] Bye...
With the patch we can got clear output,
[ 67.740553] sysrq: Trigger a crash
[ 67.744166] Kernel panic - not syncing: sysrq triggered crash
[ 67.809123] CPU1: off
[ 67.865210] CPU2: off
[ 67.909075] CPU3: off
[ 67.919123] Starting crashdump kernel...
[ 67.924900] Will call new kernel at ecc00000 from hart id 0
[ 67.932045] FDT image at fc5ee000
[ 67.935560] Bye...
Fixes: 0e105f1d0037 ("riscv: use hart id instead of cpu id on machine_kexec")
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
---
Changes from v1:
- Add Reviewed-by
---
arch/riscv/kernel/machine_kexec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
index df8e24559035..86d1b5f9dfb5 100644
--- a/arch/riscv/kernel/machine_kexec.c
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -171,7 +171,7 @@ machine_kexec(struct kimage *image)
struct kimage_arch *internal = &image->arch;
unsigned long jump_addr = (unsigned long) image->start;
unsigned long first_ind_entry = (unsigned long) &image->head;
- unsigned long this_cpu_id = smp_processor_id();
+ unsigned long this_cpu_id = __smp_processor_id();
unsigned long this_hart_id = cpuid_to_hartid_map(this_cpu_id);
unsigned long fdt_addr = internal->fdt_addr;
void *control_code_buffer = page_address(image->control_code_page);
--
2.17.1
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec()
2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian
2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian
@ 2022-07-01 12:05 ` Xianting Tian
2022-07-01 12:05 ` [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions Xianting Tian
2 siblings, 0 replies; 5+ messages in thread
From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw)
To: palmer; +Cc: guoren, linux-kernel, linux-riscv, Xianting Tian
Currently, almost all archs (x86, arm64, mips...) support fast call
of crash_kexec() when "regs && kexec_should_crash()" is true. But
RISC-V not, it can only enter crash system via panic(). However panic()
doesn't pass the regs of the real accident scene to crash_kexec(),
it caused we can't get accurate backtrace via gdb,
$ riscv64-linux-gnu-gdb vmlinux vmcore
Reading symbols from vmlinux...
[New LWP 95]
#0 console_unlock () at kernel/printk/printk.c:2557
2557 if (do_cond_resched)
(gdb) bt
#0 console_unlock () at kernel/printk/printk.c:2557
#1 0x0000000000000000 in ?? ()
With the patch we can get the accurate backtrace,
$ riscv64-linux-gnu-gdb vmlinux vmcore
Reading symbols from vmlinux...
[New LWP 95]
#0 0xffffffe00063a4e0 in test_thread (data=<optimized out>) at drivers/test_crash.c:81
81 *(int *)p = 0xdead;
(gdb)
(gdb) bt
#0 0xffffffe00064d5c0 in test_thread (data=<optimized out>) at drivers/test_crash.c:81
#1 0x0000000000000000 in ?? ()
Test code to produce NULL address dereference in test_crash.c,
void *p = NULL;
*(int *)p = 0xdead;
Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
---
arch/riscv/kernel/traps.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index b40426509244..39d0f8bba4b4 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -16,6 +16,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/irq.h>
+#include <linux/kexec.h>
#include <asm/asm-prototypes.h>
#include <asm/bug.h>
@@ -44,6 +45,9 @@ void die(struct pt_regs *regs, const char *str)
ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
+ if (regs && kexec_should_crash(current))
+ crash_kexec(regs);
+
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
--
2.17.1
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions
2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian
2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian
2022-07-01 12:05 ` [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec() Xianting Tian
@ 2022-07-01 12:05 ` Xianting Tian
2 siblings, 0 replies; 5+ messages in thread
From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw)
To: palmer; +Cc: guoren, linux-kernel, linux-riscv, Guo Ren, Arnd Bergmann
From: Guo Ren <guoren@linux.alibaba.com>
Clean up unnecessary xchg_acquire, xchg_release, and cmpxchg_release
custom definitions, because the generic implementation is the same as
the riscv custom implementation.
Before the patch:
000000000000024e <.LBB238>:
ops = xchg_acquire(pending_ipis, 0);
24e: 089937af amoswap.d a5,s1,(s2)
252: 0230000f fence r,rw
0000000000000256 <.LBB243>:
ops = xchg_release(pending_ipis, 0);
256: 0310000f fence rw,w
25a: 089934af amoswap.d s1,s1,(s2)
After the patch:
000000000000026e <.LBB245>:
ops = xchg_acquire(pending_ipis, 0);
26e: 089937af amoswap.d a5,s1,(s2)
0000000000000272 <.LBE247>:
272: 0230000f fence r,rw
0000000000000276 <.LBB249>:
ops = xchg_release(pending_ipis, 0);
276: 0310000f fence rw,w
000000000000027a <.LBB251>:
27a: 089934af amoswap.d s1,s1,(s2)
Only cmpxchg_acquire is necessary (It prevents unnecessary acquire
ordering when the value from lr is different from old).
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
---
arch/riscv/include/asm/atomic.h | 19 -----
arch/riscv/include/asm/cmpxchg.h | 116 -------------------------------
2 files changed, 135 deletions(-)
diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h
index 0dfe9d857a76..83636320ba95 100644
--- a/arch/riscv/include/asm/atomic.h
+++ b/arch/riscv/include/asm/atomic.h
@@ -249,16 +249,6 @@ c_t arch_atomic##prefix##_xchg_relaxed(atomic##prefix##_t *v, c_t n) \
return __xchg_relaxed(&(v->counter), n, size); \
} \
static __always_inline \
-c_t arch_atomic##prefix##_xchg_acquire(atomic##prefix##_t *v, c_t n) \
-{ \
- return __xchg_acquire(&(v->counter), n, size); \
-} \
-static __always_inline \
-c_t arch_atomic##prefix##_xchg_release(atomic##prefix##_t *v, c_t n) \
-{ \
- return __xchg_release(&(v->counter), n, size); \
-} \
-static __always_inline \
c_t arch_atomic##prefix##_xchg(atomic##prefix##_t *v, c_t n) \
{ \
return __xchg(&(v->counter), n, size); \
@@ -276,12 +266,6 @@ c_t arch_atomic##prefix##_cmpxchg_acquire(atomic##prefix##_t *v, \
return __cmpxchg_acquire(&(v->counter), o, n, size); \
} \
static __always_inline \
-c_t arch_atomic##prefix##_cmpxchg_release(atomic##prefix##_t *v, \
- c_t o, c_t n) \
-{ \
- return __cmpxchg_release(&(v->counter), o, n, size); \
-} \
-static __always_inline \
c_t arch_atomic##prefix##_cmpxchg(atomic##prefix##_t *v, c_t o, c_t n) \
{ \
return __cmpxchg(&(v->counter), o, n, size); \
@@ -299,12 +283,9 @@ c_t arch_atomic##prefix##_cmpxchg(atomic##prefix##_t *v, c_t o, c_t n) \
ATOMIC_OPS()
#define arch_atomic_xchg_relaxed arch_atomic_xchg_relaxed
-#define arch_atomic_xchg_acquire arch_atomic_xchg_acquire
-#define arch_atomic_xchg_release arch_atomic_xchg_release
#define arch_atomic_xchg arch_atomic_xchg
#define arch_atomic_cmpxchg_relaxed arch_atomic_cmpxchg_relaxed
#define arch_atomic_cmpxchg_acquire arch_atomic_cmpxchg_acquire
-#define arch_atomic_cmpxchg_release arch_atomic_cmpxchg_release
#define arch_atomic_cmpxchg arch_atomic_cmpxchg
#undef ATOMIC_OPS
diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h
index 12debce235e5..67ab6375b650 100644
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -44,76 +44,6 @@
_x_, sizeof(*(ptr))); \
})
-#define __xchg_acquire(ptr, new, size) \
-({ \
- __typeof__(ptr) __ptr = (ptr); \
- __typeof__(new) __new = (new); \
- __typeof__(*(ptr)) __ret; \
- switch (size) { \
- case 4: \
- __asm__ __volatile__ ( \
- " amoswap.w %0, %2, %1\n" \
- RISCV_ACQUIRE_BARRIER \
- : "=r" (__ret), "+A" (*__ptr) \
- : "r" (__new) \
- : "memory"); \
- break; \
- case 8: \
- __asm__ __volatile__ ( \
- " amoswap.d %0, %2, %1\n" \
- RISCV_ACQUIRE_BARRIER \
- : "=r" (__ret), "+A" (*__ptr) \
- : "r" (__new) \
- : "memory"); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
- __ret; \
-})
-
-#define arch_xchg_acquire(ptr, x) \
-({ \
- __typeof__(*(ptr)) _x_ = (x); \
- (__typeof__(*(ptr))) __xchg_acquire((ptr), \
- _x_, sizeof(*(ptr))); \
-})
-
-#define __xchg_release(ptr, new, size) \
-({ \
- __typeof__(ptr) __ptr = (ptr); \
- __typeof__(new) __new = (new); \
- __typeof__(*(ptr)) __ret; \
- switch (size) { \
- case 4: \
- __asm__ __volatile__ ( \
- RISCV_RELEASE_BARRIER \
- " amoswap.w %0, %2, %1\n" \
- : "=r" (__ret), "+A" (*__ptr) \
- : "r" (__new) \
- : "memory"); \
- break; \
- case 8: \
- __asm__ __volatile__ ( \
- RISCV_RELEASE_BARRIER \
- " amoswap.d %0, %2, %1\n" \
- : "=r" (__ret), "+A" (*__ptr) \
- : "r" (__new) \
- : "memory"); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
- __ret; \
-})
-
-#define arch_xchg_release(ptr, x) \
-({ \
- __typeof__(*(ptr)) _x_ = (x); \
- (__typeof__(*(ptr))) __xchg_release((ptr), \
- _x_, sizeof(*(ptr))); \
-})
-
#define __xchg(ptr, new, size) \
({ \
__typeof__(ptr) __ptr = (ptr); \
@@ -253,52 +183,6 @@
_o_, _n_, sizeof(*(ptr))); \
})
-#define __cmpxchg_release(ptr, old, new, size) \
-({ \
- __typeof__(ptr) __ptr = (ptr); \
- __typeof__(*(ptr)) __old = (old); \
- __typeof__(*(ptr)) __new = (new); \
- __typeof__(*(ptr)) __ret; \
- register unsigned int __rc; \
- switch (size) { \
- case 4: \
- __asm__ __volatile__ ( \
- RISCV_RELEASE_BARRIER \
- "0: lr.w %0, %2\n" \
- " bne %0, %z3, 1f\n" \
- " sc.w %1, %z4, %2\n" \
- " bnez %1, 0b\n" \
- "1:\n" \
- : "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
- : "rJ" ((long)__old), "rJ" (__new) \
- : "memory"); \
- break; \
- case 8: \
- __asm__ __volatile__ ( \
- RISCV_RELEASE_BARRIER \
- "0: lr.d %0, %2\n" \
- " bne %0, %z3, 1f\n" \
- " sc.d %1, %z4, %2\n" \
- " bnez %1, 0b\n" \
- "1:\n" \
- : "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
- : "rJ" (__old), "rJ" (__new) \
- : "memory"); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
- __ret; \
-})
-
-#define arch_cmpxchg_release(ptr, o, n) \
-({ \
- __typeof__(*(ptr)) _o_ = (o); \
- __typeof__(*(ptr)) _n_ = (n); \
- (__typeof__(*(ptr))) __cmpxchg_release((ptr), \
- _o_, _n_, sizeof(*(ptr))); \
-})
-
#define __cmpxchg(ptr, old, new, size) \
({ \
__typeof__(ptr) __ptr = (ptr); \
--
2.17.1
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v5 0/3] RISC-V: three fixup and cleanups
@ 2022-07-01 12:04 Xianting Tian
0 siblings, 0 replies; 5+ messages in thread
From: Xianting Tian @ 2022-07-01 12:04 UTC (permalink / raw)
To: palmer; +Cc: guoren, linux-kernel, linux-riscv
Hi Palmer and experts,
These 3 patches are some obviously fixup and cleanups, please have a look, thanks.
Xianting Tian (2):
RISC-V: use __smp_processor_id() instead of smp_processor_id()
RISC-V: Fixup fast call of crash_kexec()
Guo Ren (1):
riscv: atomic: Clean up unnecessary acquire and release definitions
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 5+ messages in thread
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