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s390/cpufeature: Convert MACHINE_HAS_SEQ_INSN to cpu_has_seq_insn()

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Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature is present.

test_facility() generates better code since it results in a static branch
without accessing memory. The branch is patched via alternatives by the
decompressor depending on the availability of the required facility.

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 15:48:47 +01:00 committed by Vasily Gorbik
parent 4a66f273c3
commit 679b110bb6
5 changed files with 13 additions and 11 deletions
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4
arch/s390/include/asm/cpufeature.h
View File

@ -9,6 +9,8 @@
#ifndef __ASM_S390_CPUFEATURE_H
#define __ASM_S390_CPUFEATURE_H
#include <asm/facility.h>
enum {
S390_CPU_FEATURE_MSA,
S390_CPU_FEATURE_VXRS,
@ -20,4 +22,6 @@ enum {
int cpu_have_feature(unsigned int nr);
#define cpu_has_seq_insn() test_facility(85)
#endif /* __ASM_S390_CPUFEATURE_H */

2
arch/s390/include/asm/setup.h
View File

@ -34,7 +34,6 @@
#define MACHINE_FLAG_SCC BIT(17)
#define MACHINE_FLAG_PCI_MIO BIT(18)
#define MACHINE_FLAG_RDP BIT(19)
#define MACHINE_FLAG_SEQ_INSN BIT(20)
#define LPP_MAGIC BIT(31)
#define LPP_PID_MASK _AC(0xffffffff, UL)
@ -96,7 +95,6 @@ extern unsigned long mio_wb_bit_mask;
#define MACHINE_HAS_SCC (get_lowcore()->machine_flags & MACHINE_FLAG_SCC)
#define MACHINE_HAS_PCI_MIO (get_lowcore()->machine_flags & MACHINE_FLAG_PCI_MIO)
#define MACHINE_HAS_RDP (get_lowcore()->machine_flags & MACHINE_FLAG_RDP)
#define MACHINE_HAS_SEQ_INSN (get_lowcore()->machine_flags & MACHINE_FLAG_SEQ_INSN)
/*
* Console mode. Override with conmode=

2
arch/s390/kernel/early.c
View File

@ -269,8 +269,6 @@ static __init void detect_machine_facilities(void)
}
if (test_facility(194))
get_lowcore()->machine_flags |= MACHINE_FLAG_RDP;
if (test_facility(85))
get_lowcore()->machine_flags |= MACHINE_FLAG_SEQ_INSN;
}
static inline void save_vector_registers(void)

11
arch/s390/kernel/ftrace.c
View File

@ -13,6 +13,7 @@
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/kmsan-checks.h>
#include <linux/cpufeature.h>
#include <linux/kprobes.h>
#include <linux/execmem.h>
#include <trace/syscall.h>
@ -69,7 +70,7 @@ static const char *ftrace_shared_hotpatch_trampoline(const char **end)
bool ftrace_need_init_nop(void)
{
return !MACHINE_HAS_SEQ_INSN;
return !cpu_has_seq_insn();
}
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
@ -189,7 +190,7 @@ static int ftrace_modify_trampoline_call(struct dyn_ftrace *rec,
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
if (MACHINE_HAS_SEQ_INSN)
if (cpu_has_seq_insn())
return ftrace_patch_branch_insn(rec->ip, old_addr, addr);
else
return ftrace_modify_trampoline_call(rec, old_addr, addr);
@ -213,8 +214,8 @@ static int ftrace_patch_branch_mask(void *addr, u16 expected, bool enable)
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
/* Expect brcl 0xf,... for the !MACHINE_HAS_SEQ_INSN case */
if (MACHINE_HAS_SEQ_INSN)
/* Expect brcl 0xf,... for the !cpu_has_seq_insn() case */
if (cpu_has_seq_insn())
return ftrace_patch_branch_insn(rec->ip, addr, 0);
else
return ftrace_patch_branch_mask((void *)rec->ip, 0xc0f4, false);
@ -234,7 +235,7 @@ static int ftrace_make_trampoline_call(struct dyn_ftrace *rec, unsigned long add
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
if (MACHINE_HAS_SEQ_INSN)
if (cpu_has_seq_insn())
return ftrace_patch_branch_insn(rec->ip, 0, addr);
else
return ftrace_make_trampoline_call(rec, addr);

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

@ -13,6 +13,7 @@
#include <linux/ptrace.h>
#include <linux/preempt.h>
#include <linux/stop_machine.h>
#include <linux/cpufeature.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <linux/extable.h>
@ -153,7 +154,7 @@ void arch_arm_kprobe(struct kprobe *p)
{
struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
if (MACHINE_HAS_SEQ_INSN) {
if (cpu_has_seq_insn()) {
swap_instruction(&args);
text_poke_sync();
} else {
@ -166,7 +167,7 @@ void arch_disarm_kprobe(struct kprobe *p)
{
struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
if (MACHINE_HAS_SEQ_INSN) {
if (cpu_has_seq_insn()) {
swap_instruction(&args);
text_poke_sync();
} else {