From: Vincent Chen vincent.chen@sifive.com
mainline inclusion from mainline-5.10.62 commit 921c2533aa3a980daa9942f9476e008ddcff65be bugzilla: 182217 https://gitee.com/openeuler/kernel/issues/I4EFOS
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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commit 379eb01c21795edb4ca8d342503bd2183a19ec3a upstream.
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 vincent.chen@sifive.com Reviewed-by: Jisheng Zhang jszhang@kernel.org Fixes: b8c8a9590e4f ("RISC-V: Add FP register ptrace support for gdb.") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmerdabbelt@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- arch/riscv/kernel/ptrace.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index 2d6395f5ad54..69678ab6457d 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