Hi Andy,
For some reason I was looking closely at this patch today.
On 1/25/23 06:20, Andy Chiu wrote:
/* Whitelist the fstate from the task_struct for hardened usercopy */
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
index df1aa589b7fd..69e24140195d 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -8,6 +8,7 @@
#include <linux/jump_label.h>
#include <linux/sched/task_stack.h>
+#include <asm/vector.h>
#include <asm/hwcap.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
@@ -68,6 +69,21 @@ static __always_inline bool has_fpu(void) { return false; }
#define __switch_to_fpu(__prev, __next) do { } while (0)
#endif
+#ifdef CONFIG_RISCV_ISA_V
+static inline void __switch_to_vector(struct task_struct *prev,
+ struct task_struct *next)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(prev);
+ if (unlikely(regs->status & SR_SD))
Do we really need to check SR_SD, isn't checking for SR_VS_DIRTY enough.
If yes, we can remove the check here and keep the existing one on
vstate_save()
+ vstate_save(prev, regs);
+ vstate_restore(next, task_pt_regs(next));
+}
+#else /* ! CONFIG_RISCV_ISA_V */
+#define __switch_to_vector(__prev, __next) do { } while (0)
+#endif /* CONFIG_RISCV_ISA_V */
+
Can we de-lutter switch_to.h some more and move both the definitions of
__switch_to_vector into vector.h ?
extern struct task_struct *__switch_to(struct task_struct *,
struct task_struct *);
@@ -77,6 +93,8 @@ do { \
struct task_struct *__next = (next); \
if (has_fpu()) \
__switch_to_fpu(__prev, __next); \
+ if (has_vector()) \
+ __switch_to_vector(__prev, __next); \
((last) = __switch_to(__prev, __next)); \
} while (0)
