mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-29 02:14:03 -04:00
Code Issues Packages Projects Releases Wiki Activity

s390/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS

Browse Source 
Convert s390's preempt_count to 64 bit, and change the preempt
primitives accordingly.

[boqun: Apply the corrected comment for asm block]
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804161447.84806-13-boqun@kernel.org
This commit is contained in:
Heiko Carstens
2026-08-04 09:14:34 -07:00
committed by Peter Zijlstra
parent 264bbd32a3
commit 3484440a7b
3 changed files with 30 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
arch/s390/Kconfig
View File

@@ -273,6 +273,7 @@ config S390
select PCI_MSI if PCI
select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
select PCI_QUIRKS if PCI
select HAS_SEPARATE_PREEMPT_RESCHED_BITS
select SPARSE_IRQ
select SWIOTLB
select SYSCTL_EXCEPTION_TRACE

13
arch/s390/include/asm/lowcore.h
View File

@@ -160,10 +160,15 @@ struct lowcore {
/* SMP info area */
__u32 cpu_nr; /* 0x03a0 */
__u32 softirq_pending; /* 0x03a4 */
__s32 preempt_count; /* 0x03a8 */
__u32 spinlock_lockval; /* 0x03ac */
__u32 spinlock_index; /* 0x03b0 */
__u8 pad_0x03b4[0x03b8-0x03b4]; /* 0x03b4 */
union {
struct {
__u32 need_resched; /* 0x03a8 */
__u32 count; /* 0x03ac */
} preempt;
__u64 preempt_count; /* 0x03a8 */
};
__u32 spinlock_lockval; /* 0x03b0 */
__u32 spinlock_index; /* 0x03b4 */
__u64 percpu_offset; /* 0x03b8 */
__u8 percpu_register; /* 0x03c0 */
__u8 pad_0x03c1[0x0400-0x03c1]; /* 0x03c1 */

43
arch/s390/include/asm/preempt.h
View File

@@ -8,11 +8,8 @@
#include <asm/cmpxchg.h>
#include <asm/march.h>
/*
* Use MSB so it is possible to read preempt_count with LLGT which
* reads the least significant 31 bits with a single instruction.
*/
#define PREEMPT_NEED_RESCHED 0x80000000
/* Use MSB for PREEMPT_NEED_RESCHED mostly because it is available. */
#define PREEMPT_NEED_RESCHED 0x8000000000000000UL
/*
* We use the PREEMPT_NEED_RESCHED bit as an inverted NEED_RESCHED such
@@ -26,25 +23,25 @@
*/
static __always_inline int preempt_count(void)
{
unsigned long lc_preempt, count;
unsigned long lc_preempt;
int count;
BUILD_BUG_ON(sizeof_field(struct lowcore, preempt_count) != sizeof(int));
lc_preempt = offsetof(struct lowcore, preempt_count);
/* READ_ONCE(get_lowcore()->preempt_count) & ~PREEMPT_NEED_RESCHED */
lc_preempt = offsetof(struct lowcore, preempt.count);
/* READ_ONCE(get_lowcore()->preempt.count) (without PREEMPT_NEED_RESCHED) */
asm_inline(
ALTERNATIVE("llgt %[count],%[offzero](%%r0)\n",
"llgt %[count],%[offalt](%%r0)\n",
ALTERNATIVE("ly %[count],%[offzero](%%r0)\n",
"ly %[count],%[offalt](%%r0)\n",
ALT_FEATURE(MFEATURE_LOWCORE))
: [count] "=d" (count)
: [offzero] "i" (lc_preempt),
[offalt] "i" (lc_preempt + LOWCORE_ALT_ADDRESS),
"m" (((struct lowcore *)0)->preempt_count));
"m" (((struct lowcore *)0)->preempt.count));
return count;
}
static __always_inline void preempt_count_set(int pc)
static __always_inline void preempt_count_set(unsigned long pc)
{
int old, new;
unsigned long old, new;
old = READ_ONCE(get_lowcore()->preempt_count);
do {
@@ -63,12 +60,12 @@ static __always_inline void preempt_count_set(int pc)
static __always_inline void set_preempt_need_resched(void)
{
__atomic_and(~PREEMPT_NEED_RESCHED, &get_lowcore()->preempt_count);
__atomic64_and(~PREEMPT_NEED_RESCHED, (long *)&get_lowcore()->preempt_count);
}
static __always_inline void clear_preempt_need_resched(void)
{
__atomic_or(PREEMPT_NEED_RESCHED, &get_lowcore()->preempt_count);
__atomic64_or(PREEMPT_NEED_RESCHED, (long *)&get_lowcore()->preempt_count);
}
static __always_inline bool test_preempt_need_resched(void)
@@ -88,8 +85,8 @@ static __always_inline void __preempt_count_add(int val)
lc_preempt = offsetof(struct lowcore, preempt_count);
asm_inline(
ALTERNATIVE("asi %[offzero](%%r0),%[val]\n",
"asi %[offalt](%%r0),%[val]\n",
ALTERNATIVE("agsi %[offzero](%%r0),%[val]\n",
"agsi %[offalt](%%r0),%[val]\n",
ALT_FEATURE(MFEATURE_LOWCORE))
: "+m" (((struct lowcore *)0)->preempt_count)
: [offzero] "i" (lc_preempt), [val] "i" (val),
@@ -98,7 +95,7 @@ static __always_inline void __preempt_count_add(int val)
return;
}
}
__atomic_add(val, &get_lowcore()->preempt_count);
__atomic64_add(val, (long *)&get_lowcore()->preempt_count);
}
static __always_inline void __preempt_count_sub(int val)
@@ -119,15 +116,15 @@ static __always_inline bool __preempt_count_dec_and_test(void)
lc_preempt = offsetof(struct lowcore, preempt_count);
asm_inline(
ALTERNATIVE("alsi %[offzero](%%r0),%[val]\n",
"alsi %[offalt](%%r0),%[val]\n",
ALTERNATIVE("algsi %[offzero](%%r0),%[val]\n",
"algsi %[offalt](%%r0),%[val]\n",
ALT_FEATURE(MFEATURE_LOWCORE))
: "=@cc" (cc), "+m" (((struct lowcore *)0)->preempt_count)
: [offzero] "i" (lc_preempt), [val] "i" (-1),
[offalt] "i" (lc_preempt + LOWCORE_ALT_ADDRESS));
return (cc == 0) || (cc == 2);
#else
return __atomic_add_const_and_test(-1, &get_lowcore()->preempt_count);
return __atomic64_add_const_and_test(-1, (long *)&get_lowcore()->preempt_count);
#endif
}
@@ -141,7 +138,7 @@ static __always_inline bool should_resched(int preempt_offset)
static __always_inline int __preempt_count_add_return(int val)
{
return val + __atomic_add(val, &get_lowcore()->preempt_count);
return val + __atomic64_add(val, (long *)&get_lowcore()->preempt_count);
}
static __always_inline int __preempt_count_sub_return(int val)