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s390/bear: Convert cpu_has_bear() to cpu feature function

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Get rid of the cpu_has_bear jump label and convert cpu_has_bear() to a cpu
feature function using test_facility() and with that use a static branch.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2025-02-07 15:49:09 +01:00 committed by Vasily Gorbik
parent db14f78ecb
commit 841f35a08d
7 changed files with 11 additions and 13 deletions
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1
arch/s390/include/asm/cpufeature.h
View File

@ -22,6 +22,7 @@ enum {
int cpu_have_feature(unsigned int nr);
#define cpu_has_bear() test_facility(193)
#define cpu_has_edat1() test_facility(8)
#define cpu_has_edat2() test_facility(78)
#define cpu_has_gs() test_facility(133)

5
arch/s390/kernel/irq.c
View File

@ -9,6 +9,7 @@
*/
#include <linux/kernel_stat.h>
#include <linux/cpufeature.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
@ -150,7 +151,7 @@ void noinstr do_io_irq(struct pt_regs *regs)
if (user_mode(regs)) {
update_timer_sys();
if (static_branch_likely(&cpu_has_bear))
if (cpu_has_bear())
current->thread.last_break = regs->last_break;
}
@ -186,7 +187,7 @@ void noinstr do_ext_irq(struct pt_regs *regs)
if (user_mode(regs)) {
update_timer_sys();
if (static_branch_likely(&cpu_has_bear))
if (cpu_has_bear())
current->thread.last_break = regs->last_break;
}

6
arch/s390/kernel/setup.c
View File

@ -181,8 +181,6 @@ unsigned long __bootdata_preserved(MODULES_END);
struct lowcore *lowcore_ptr[NR_CPUS];
EXPORT_SYMBOL(lowcore_ptr);
DEFINE_STATIC_KEY_FALSE(cpu_has_bear);
/*
* The Write Back bit position in the physaddr is given by the SLPC PCI.
* Leaving the mask zero always uses write through which is safe
@ -982,10 +980,6 @@ void __init setup_arch(char **cmdline_p)
numa_setup();
smp_detect_cpus();
topology_init_early();
if (test_facility(193))
static_branch_enable(&cpu_has_bear);
setup_protection_map();
/*
* Create kernel page tables.

3
arch/s390/kernel/syscall.c
View File

@ -12,6 +12,7 @@
* platform.
*/
#include <linux/cpufeature.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
@ -127,7 +128,7 @@ void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
regs->psw = get_lowcore()->svc_old_psw;
regs->int_code = get_lowcore()->svc_int_code;
update_timer_sys();
if (static_branch_likely(&cpu_has_bear))
if (cpu_has_bear())
current->thread.last_break = regs->last_break;
local_irq_enable();

3
arch/s390/kernel/traps.c
View File

@ -15,6 +15,7 @@
*/
#include "asm/irqflags.h"
#include "asm/ptrace.h"
#include <linux/cpufeature.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/randomize_kstack.h>
@ -341,7 +342,7 @@ void noinstr __do_pgm_check(struct pt_regs *regs)
if (user_mode(regs)) {
update_timer_sys();
if (!static_branch_likely(&cpu_has_bear)) {
if (!cpu_has_bear()) {
if (regs->last_break < 4096)
regs->last_break = 1;
}

4
arch/s390/mm/dump_pagetables.c
View File

@ -84,7 +84,7 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr)
* in which case we have two lpswe instructions in lowcore that need
* to be executable.
*/
if (addr == PAGE_SIZE && (nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear)))
if (addr == PAGE_SIZE && (nospec_uses_trampoline() || !cpu_has_bear()))
return;
WARN_ONCE(IS_ENABLED(CONFIG_DEBUG_WX),
"s390/mm: Found insecure W+X mapping at address %pS\n",
@ -178,7 +178,7 @@ bool ptdump_check_wx(void)
return false;
} else {
pr_info("Checked W+X mappings: passed, no %sW+X pages found\n",
(nospec_uses_trampoline() || !static_key_enabled(&cpu_has_bear)) ?
(nospec_uses_trampoline() || !cpu_has_bear()) ?
"unexpected " : "");
return true;

2
arch/s390/mm/vmem.c
View File

@ -660,7 +660,7 @@ void __init vmem_map_init(void)
* prefix page is used to return to the previous context with
* an LPSWE instruction and therefore must be executable.
*/
if (!static_key_enabled(&cpu_has_bear))
if (!cpu_has_bear())
set_memory_x(0, 1);
if (debug_pagealloc_enabled())
__set_memory_4k(__va(0), absolute_pointer(__va(0)) + ident_map_size);