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

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

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.

Thanks,
Nick