Re: [PATCH 03/10] powerpc/64e/interrupt: use new interrupt return

Excerpts from Christophe Leroy's message of March 16, 2021 5:29 pm:

Le 16/03/2021 à 08:25, Nicholas Piggin a écrit :

quoted

Excerpts from Nicholas Piggin's message of March 16, 2021 5:04 pm:

quoted

Excerpts from Christophe Leroy's message of March 15, 2021 11:30 pm:

quoted

Le 15/03/2021 à 04:17, Nicholas Piggin a écrit :

quoted

Update the new C and asm interrupt return code to account for 64e
specifics, switch over to use it.

The now-unused old ret_from_except code, that was moved to 64e after the
64s conversion, is removed.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
   arch/powerpc/include/asm/asm-prototypes.h |   2 -
   arch/powerpc/kernel/entry_64.S            |   9 +-
   arch/powerpc/kernel/exceptions-64e.S      | 321 ++--------------------
   arch/powerpc/kernel/interrupt.c           |  27 +-
   arch/powerpc/kernel/irq.c                 |  76 -----
   5 files changed, 56 insertions(+), 379 deletions(-)

diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index fbabb49888d3..ae7b058b2970 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c

@@ -235,6 +235,10 @@ static notrace void booke_load_dbcr0(void)
   #endif
   }
   
+/* temporary hack for context tracking, removed in later patch */
+#include <linux/sched/debug.h>
+asmlinkage __visible void __sched schedule_user(void);
+
   /*
    * This should be called after a syscall returns, with r3 the return value
    * from the syscall. If this function returns non-zero, the system call

@@ -292,7 +296,11 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
   	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
   		local_irq_enable();
   		if (ti_flags & _TIF_NEED_RESCHED) {
+#ifdef CONFIG_PPC_BOOK3E_64
+			schedule_user();
+#else
   			schedule();
+#endif
   		} else {
   			/*
   			 * SIGPENDING must restore signal handler function

@@ -360,7 +368,6 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
   	return ret;
   }
   
-#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not yet using this */
   notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr)
   {
   	unsigned long ti_flags;

@@ -372,7 +379,9 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
   	BUG_ON(!(regs->msr & MSR_PR));
   	BUG_ON(!FULL_REGS(regs));
   	BUG_ON(arch_irq_disabled_regs(regs));
+#ifdef CONFIG_PPC_BOOK3S_64

Shouldn't this go away in patch 6 as well ?
Or is that needed at all ? In syscall_exit_prepare() it is not ifdefed .

Hmm, not sure. I'll take a look. It probably shouldn't be ifdefed at all
but definitely by the end it should run without warning.

Oh I got confused and thought that was the syscall exit. Interrupt exit
has to keep this until patch 6 because 64e context tracking does
everything in interrupt wrappers, so by the time we get here it will
already be set to CONTEXT_USER.

ok, but that it has to go in patch 6 ? At the time being the #ifdef is still there at the end of the 
series

Yes, that was an oversight. I'll remove it.

Thanks,
Nick