diff options
| author | Heiko Carstens <hca@linux.ibm.com> | 2023-10-12 10:40:41 +0300 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2023-10-23 19:21:22 +0300 |
| commit | 4416d2ed816699b8e7491f1e8e8b15f69685af57 (patch) | |
| tree | 4a5131f0b9c63ead952d1bd4e8bdde56e92f7392 /arch/s390/mm | |
| parent | 9641613f48bbf8626355118de58f96eec5aebf49 (diff) | |
| download | linux-4416d2ed816699b8e7491f1e8e8b15f69685af57.tar.xz | |
s390/mm,fault: use static key for store indication
Generate slightly better code by using a static key to implement store
indication. This allows to get rid of a memory access on the hot path.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/fault.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index ba2056b35910..5466a30d1ec4 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -15,6 +15,7 @@ #include <linux/signal.h> #include <linux/sched.h> #include <linux/sched/debug.h> +#include <linux/jump_label.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/string.h> @@ -60,12 +61,12 @@ enum fault_type { GMAP_FAULT, }; -static unsigned long store_indication __read_mostly; +static DEFINE_STATIC_KEY_FALSE(have_store_indication); static int __init fault_init(void) { if (test_facility(75)) - store_indication = 0xc00; + static_branch_enable(&have_store_indication); return 0; } early_initcall(fault_init); @@ -104,11 +105,13 @@ static unsigned long get_fault_address(struct pt_regs *regs) return trans_exc_code & __FAIL_ADDR_MASK; } -static bool fault_is_write(struct pt_regs *regs) +static __always_inline bool fault_is_write(struct pt_regs *regs) { unsigned long trans_exc_code = regs->int_parm_long; - return (trans_exc_code & store_indication) == 0x400; + if (static_branch_likely(&have_store_indication)) + return (trans_exc_code & 0xc00) == 0x400; + return false; } static int bad_address(void *p) |