Le 27/08/2019 à 15:55, Nicholas Piggin a écrit :
System call entry and particularly exit code is beyond the limit of what
is reasonable to implement in asm.
This conversion moves all conditional branches out of the asm code,
except for the case that all GPRs should be restored at exit.
Null syscall test is about 5% faster after this patch, because the exit
work is handled under local_irq_disable, and the hard mask and pending
interrupt replay is handled after that, which avoids games with MSR.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
Changes since v1:
- Improve changelog
- Lot of code cleanups, moving helpers out to proper header locations,
etc (Christophe).
- Split unnecessary change that affected ppc32 out. I will submit it
independently (Christophe).
arch/powerpc/include/asm/asm-prototypes.h | 11 -
.../powerpc/include/asm/book3s/64/kup-radix.h | 12 +-
arch/powerpc/include/asm/cputime.h | 22 ++
arch/powerpc/include/asm/ptrace.h | 3 +
arch/powerpc/include/asm/signal.h | 2 +
arch/powerpc/include/asm/switch_to.h | 5 +
arch/powerpc/include/asm/time.h | 3 +
arch/powerpc/kernel/Makefile | 3 +-
arch/powerpc/kernel/entry_64.S | 340 +++---------------
arch/powerpc/kernel/signal.h | 2 -
arch/powerpc/kernel/syscall_64.c | 177 +++++++++
11 files changed, 273 insertions(+), 307 deletions(-)
create mode 100644 arch/powerpc/kernel/syscall_64.c
diff --git a/arch/powerpc/include/asm/asm-prototypes.h
b/arch/powerpc/include/asm/asm-prototypes.h
index ec1c97a8e8cb..f00ef8924a99 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -92,14 +92,6 @@ long sys_switch_endian(void);
notrace unsigned int __check_irq_replay(void);
void notrace restore_interrupts(void);
-/* ptrace */
-long do_syscall_trace_enter(struct pt_regs *regs);
-void do_syscall_trace_leave(struct pt_regs *regs);
-
-/* process */
-void restore_math(struct pt_regs *regs);
-void restore_tm_state(struct pt_regs *regs);
-
/* prom_init (OpenFirmware) */
unsigned long __init prom_init(unsigned long r3, unsigned long r4,
unsigned long pp,
@@ -110,9 +102,6 @@ unsigned long __init prom_init(unsigned long r3, unsigned
long r4,
void __init early_setup(unsigned long dt_ptr);
void early_setup_secondary(void);
-/* time */
-void accumulate_stolen_time(void);
-
/* misc runtime */
extern u64 __bswapdi2(u64);
extern s64 __lshrdi3(s64, int);
diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h
b/arch/powerpc/include/asm/book3s/64/kup-radix.h
index f254de956d6a..ef2e65ea8a73 100644
--- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
@@ -3,6 +3,7 @@
#define _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H
#include <linux/const.h>
+#include <asm/reg.h>
#define AMR_KUAP_BLOCK_READ UL(0x4000000000000000)
#define AMR_KUAP_BLOCK_WRITE UL(0x8000000000000000)
@@ -56,7 +57,16 @@
#ifdef CONFIG_PPC_KUAP
-#include <asm/reg.h>
+#include <asm/mmu.h>
+#include <asm/ptrace.h>
+
+static inline void kuap_check_amr(void)
+{
+#ifdef CONFIG_PPC_KUAP_DEBUG
+ if (mmu_has_feature(MMU_FTR_RADIX_KUAP))
Better:
if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) &&
mmu_has_feature(MMU_FTR_RADIX_KUAP))
+ WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
+#endif
+}
/*
* We support individually allowing read or write, but we don't support
nesting
diff --git a/arch/powerpc/include/asm/cputime.h
b/arch/powerpc/include/asm/cputime.h
index 2431b4ada2fa..f3aa9db1a3cc 100644
--- a/arch/powerpc/include/asm/cputime.h
+++ b/arch/powerpc/include/asm/cputime.h
@@ -60,6 +60,28 @@ static inline void arch_vtime_task_switch(struct task_struct
*prev)
}
#endif
+static inline void account_cpu_user_entry(void)
+{
+ unsigned long tb = mftb();
+
+ get_accounting(current)->utime += (tb -
get_accounting(current)->starttime_user);
+ get_accounting(current)->starttime = tb;
+}
Can you check the generated assembly ? I remember having bad result with
get_accouting() being used several times in a arch_vtime_task_switch()
before commit 60f1d2893ee6 ("powerpc/time: inline
arch_vtime_task_switch()")
Regardless, I think it would look better as:
static inline void account_cpu_user_entry(void)
{
unsigned long tb = mftb();
struct cpu_accounting_data *acct = get_accounting(current);
acct->utime += (tb - acct->starttime_user);
acct->starttime = tb;
}
+static inline void account_cpu_user_exit(void)
+{
+ unsigned long tb = mftb();
+
+ get_accounting(current)->stime += (tb -
get_accounting(current)->starttime);
+ get_accounting(current)->starttime_user = tb;
+}
Same here.
Christophe
