diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl index 3fed97478058..f31b7afffc34 100644 --- a/arch/alpha/kernel/syscalls/syscall.tbl +++ b/arch/alpha/kernel/syscalls/syscall.tbl @@ -510,3 +510,4 @@ 578 common file_getattr sys_file_getattr 579 common file_setattr sys_file_setattr 580 common listns sys_listns +581 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index fd09afae72a2..94351e22bfcf 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -485,3 +485,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/arm64/tools/syscall_32.tbl b/arch/arm64/tools/syscall_32.tbl index 8cdfe5d4dac9..62d93d88e0fe 100644 --- a/arch/arm64/tools/syscall_32.tbl +++ b/arch/arm64/tools/syscall_32.tbl @@ -482,3 +482,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl index 871a5d67bf41..248934257101 100644 --- a/arch/m68k/kernel/syscalls/syscall.tbl +++ b/arch/m68k/kernel/syscalls/syscall.tbl @@ -470,3 +470,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl index 022fc85d94b3..223d26303627 100644 --- a/arch/microblaze/kernel/syscalls/syscall.tbl +++ b/arch/microblaze/kernel/syscalls/syscall.tbl @@ -476,3 +476,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index 8cedc83c3266..7430714e2b8f 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -409,3 +409,4 @@ 468 n32 file_getattr sys_file_getattr 469 n32 file_setattr sys_file_setattr 470 n32 listns sys_listns +471 n32 rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl index 9b92bddf06b5..630aab9e5425 100644 --- a/arch/mips/kernel/syscalls/syscall_n64.tbl +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl @@ -385,3 +385,4 @@ 468 n64 file_getattr sys_file_getattr 469 n64 file_setattr sys_file_setattr 470 n64 listns sys_listns +471 n64 rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index f810b8a55716..128653112284 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -458,3 +458,4 @@ 468 o32 file_getattr sys_file_getattr 469 o32 file_setattr sys_file_setattr 470 o32 listns sys_listns +471 o32 rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl index 39bdacaa530b..f6e2d0379d57 100644 --- a/arch/parisc/kernel/syscalls/syscall.tbl +++ b/arch/parisc/kernel/syscalls/syscall.tbl @@ -469,3 +469,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl index ec4458cdb97b..4fcc7c58a105 100644 --- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl @@ -561,3 +561,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 nospu rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl index 417ed16b3c63..09a7ef04d979 100644 --- a/arch/s390/kernel/syscalls/syscall.tbl +++ b/arch/s390/kernel/syscalls/syscall.tbl @@ -397,3 +397,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl index 969c11325ade..70b315cbe710 100644 --- a/arch/sh/kernel/syscalls/syscall.tbl +++ b/arch/sh/kernel/syscalls/syscall.tbl @@ -474,3 +474,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl index 39aa26b6a50b..d5b1a7198410 100644 --- a/arch/sparc/kernel/syscalls/syscall.tbl +++ b/arch/sparc/kernel/syscalls/syscall.tbl @@ -516,3 +516,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index e979a3eac7a3..f832ebd2d79b 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -476,3 +476,4 @@ 468 i386 file_getattr sys_file_getattr 469 i386 file_setattr sys_file_setattr 470 i386 listns sys_listns +471 i386 rseq_slice_yield sys_rseq_slice_yield diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 8a4ac4841be6..524155d655da 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -395,6 +395,7 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield # # Due to a historical design error, certain syscalls are numbered differently diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl index 438a3b170402..a9bca4e484de 100644 --- a/arch/xtensa/kernel/syscalls/syscall.tbl +++ b/arch/xtensa/kernel/syscalls/syscall.tbl @@ -441,3 +441,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield diff --git a/include/linux/rseq_types.h b/include/linux/rseq_types.h index 67e40c059b1b..8c540e775161 100644 --- a/include/linux/rseq_types.h +++ b/include/linux/rseq_types.h @@ -89,9 +89,11 @@ union rseq_slice_state { /** * struct rseq_slice - Status information for rseq time slice extension * @state: Time slice extension state + * @yielded: Indicator for rseq_slice_yield() */ struct rseq_slice { union rseq_slice_state state; + u8 yielded; }; /** diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index cf84d98964b2..6c8a570cf44a 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -961,6 +961,7 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags, unsigned mask, struct statx __user *buffer); asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len, int flags, uint32_t sig); +asmlinkage long sys_rseq_slice_yield(void); asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags); asmlinkage long sys_open_tree_attr(int dfd, const char __user *path, unsigned flags, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 942370b3f5d2..a627acc8fb5f 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -860,8 +860,11 @@ __SYSCALL(__NR_file_setattr, sys_file_setattr) #define __NR_listns 470 __SYSCALL(__NR_listns, sys_listns) +#define __NR_rseq_slice_yield 471 +__SYSCALL(__NR_rseq_slice_yield, sys_rseq_slice_yield) + #undef __NR_syscalls -#define __NR_syscalls 471 +#define __NR_syscalls 472 /* * 32 bit systems traditionally used different diff --git a/kernel/rseq.c b/kernel/rseq.c index 09848bb14ec2..d8e1992edffa 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -553,6 +553,27 @@ die: return -EFAULT; } +/** + * sys_rseq_slice_yield - yield the current processor side effect free if a + * task granted with a time slice extension is done with + * the critical work before being forced out. + * + * Return: 1 if the task successfully yielded the CPU within the granted slice. + * 0 if the slice extension was either never granted or was revoked by + * going over the granted extension, using a syscall other than this one + * or being scheduled out earlier due to a subsequent interrupt. + * + * The syscall does not schedule because the syscall entry work immediately + * relinquishes the CPU and schedules if required. + */ +SYSCALL_DEFINE0(rseq_slice_yield) +{ + int yielded = !!current->rseq.slice.yielded; + + current->rseq.slice.yielded = 0; + return yielded; +} + static int __init rseq_slice_cmdline(char *str) { bool on; diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index bf5d05c635ff..add3032da16f 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -390,6 +390,7 @@ COND_SYSCALL(setuid16); /* restartable sequence */ COND_SYSCALL(rseq); +COND_SYSCALL(rseq_slice_yield); COND_SYSCALL(uretprobe); COND_SYSCALL(uprobe); diff --git a/scripts/syscall.tbl b/scripts/syscall.tbl index e74868be513c..7a42b32b6577 100644 --- a/scripts/syscall.tbl +++ b/scripts/syscall.tbl @@ -411,3 +411,4 @@ 468 common file_getattr sys_file_getattr 469 common file_setattr sys_file_setattr 470 common listns sys_listns +471 common rseq_slice_yield sys_rseq_slice_yield