Le 22/06/2021 à 10:54, Nicholas Piggin a écrit :
Excerpts from Christophe Leroy's message of June 22, 2021 4:47 pm:
Le 22/06/2021 à 08:04, Nicholas Piggin a écrit :
The PPC_RFI_SRR_DEBUG check added by patch "powerpc/64s: avoid reloading
(H)SRR registers if they are still valid" has a few deficiencies. It
does not fix the actual problem, it's not enabled by default, and it
causes a program check interrupt which can cause more difficulties.
However there are a lot of paths which may clobber SRRs or change return
regs, and difficult to have a high confidence that all paths are covered
without wider testing.
Add a relatively low overhead always-enabled check that catches most
such cases, reports once, and fixes it so the kernel can continue.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/kernel/interrupt.c | 58 +++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index 05fa3ae56e25..5920a3e8d1d5 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -231,6 +231,56 @@ static notrace void booke_load_dbcr0(void)
#endif
}
+#include <linux/sched/debug.h> /* for show_regs */
+static void check_return_regs_valid(struct pt_regs *regs)
+{
+#ifdef CONFIG_PPC_BOOK3S_64
+ static bool warned = false;
+
+ if (regs->trap == 0x980 || regs->trap == 0xe00 || regs->trap == 0xe20 ||
+ regs->trap == 0xe40 || regs->trap == 0xe60 || regs->trap == 0xe80 ||
+ regs->trap == 0xea0 || regs->trap == 0xf80 || regs->trap == 0x1200
||
+ regs->trap == 0x1500 || regs->trap == 0x1600 || regs->trap ==
0x1800) {
Can you use names defined in asm/interrupt.h instead of raw values ?
Some are already there, others can be added.
Good idea. Could go into a helper too actually.
I wanted to clean up the KVM definitions and unify them with interrupt.h
defs but that's a bit of churn. Can I get to that in the next merge or
so?
Sure
Christophe
