path: root/arch
diff options
authorVincent Chen <>2021-08-03 17:27:51 +0800
committerPalmer Dabbelt <>2021-08-24 20:54:10 -0700
commit379eb01c21795edb4ca8d342503bd2183a19ec3a (patch)
tree6d168ff8dbf5450ccebf46f29616ac35002cf458 /arch
parentaa3e1ba32e553e611a58145c2eb349802feaa6eb (diff)
riscv: Ensure the value of FP registers in the core dump file is up to date
The value of FP registers in the core dump file comes from the thread.fstate. However, kernel saves the FP registers to the thread.fstate only before scheduling out the process. If no process switch happens during the exception handling process, kernel will not have a chance to save the latest value of FP registers to thread.fstate. It will cause the value of FP registers in the core dump file may be incorrect. To solve this problem, this patch force lets kernel save the FP register into the thread.fstate if the target task_struct equals the current. Signed-off-by: Vincent Chen <> Reviewed-by: Jisheng Zhang <> Fixes: b8c8a9590e4f ("RISC-V: Add FP register ptrace support for gdb.") Cc: Signed-off-by: Palmer Dabbelt <>
Diffstat (limited to 'arch')
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
index 1a85305720e8..9c0511119bad 100644
--- a/arch/riscv/kernel/ptrace.c
+++ b/arch/riscv/kernel/ptrace.c
@@ -10,6 +10,7 @@
#include <asm/ptrace.h>
#include <asm/syscall.h>
#include <asm/thread_info.h>
+#include <asm/switch_to.h>
#include <linux/audit.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
@@ -56,6 +57,9 @@ static int riscv_fpr_get(struct task_struct *target,
struct __riscv_d_ext_state *fstate = &target->thread.fstate;
+ if (target == current)
+ fstate_save(current, task_pt_regs(current));
membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
membuf_store(&to, fstate->fcsr);
return membuf_zero(&to, 4); // explicitly pad