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Wed, 22 Jan 2025 14:56:55 -0800 (PST) From: Charlie Jenkins Date: Wed, 22 Jan 2025 14:56:20 -0800 Subject: [PATCH 1/4] riscv: entry: Convert ret_from_fork() to C Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250122-riscv_optimize_entry-v1-1-4ee95559cfd0@rivosinc.com> References: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> In-Reply-To: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> To: Paul Walmsley , Palmer Dabbelt , Huacai Chen , WANG Xuerui , Thomas Gleixner , Peter Zijlstra , Andy Lutomirski , Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, Charlie Jenkins X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3438; i=charlie@rivosinc.com; h=from:subject:message-id; bh=rV9JUhm8W3Bx7rnRIzGCq2bwJctlTEtmatZOhNjH0vc=; b=owGbwMvMwCXWx5hUnlvL8Y3xtFoSQ/rE8s3MIQ08j0o/nwm++ubjMauZxccEN91XPGF74+yfn ewBNxhfdpSyMIhxMciKKbLwXGtgbr2jX3ZUtGwCzBxWJpAhDFycAjCRU7YMf7izZz+fvbMn6Tjb s5lz+eSSgzfZ1B4I++FZYx1kl/riy1xGhpMFnZuYvBcrfshj37l/8YZJ0kmhD5nP2Xm+tzAqnJ4 XwgsA X-Developer-Key: i=charlie@rivosinc.com; a=openpgp; fpr=7D834FF11B1D8387E61C776FFB10D1F27D6B1354 Move the main section of ret_from_fork() to C to allow inlining of syscall_exit_to_user_mode(). Signed-off-by: Charlie Jenkins Reviewed-by: Alexandre Ghiti --- arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/kernel/entry.S | 15 ++++++--------- arch/riscv/kernel/process.c | 14 ++++++++++++-- 3 files changed, 19 insertions(+), 11 deletions(-) diff --git a/arch/riscv/include/asm/asm-prototypes.h b/arch/riscv/include/a= sm/asm-prototypes.h index cd627ec289f163a630b73dd03dd52a6b28692997..733ff609778797001006c33bba9= e3cc5b1f15387 100644 --- a/arch/riscv/include/asm/asm-prototypes.h +++ b/arch/riscv/include/asm/asm-prototypes.h @@ -52,6 +52,7 @@ DECLARE_DO_ERROR_INFO(do_trap_ecall_s); DECLARE_DO_ERROR_INFO(do_trap_ecall_m); DECLARE_DO_ERROR_INFO(do_trap_break); =20 +asmlinkage void ret_from_fork(void *fn_arg, int (*fn)(void *), struct pt_r= egs *regs); asmlinkage void handle_bad_stack(struct pt_regs *regs); asmlinkage void do_page_fault(struct pt_regs *regs); asmlinkage void do_irq(struct pt_regs *regs); diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 33a5a9f2a0d4e1eeccfb3621b9e518b88e1b0704..9225c322279aa90e737b1d7144d= b084319cf8103 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -319,17 +319,14 @@ SYM_CODE_END(handle_kernel_stack_overflow) ASM_NOKPROBE(handle_kernel_stack_overflow) #endif =20 -SYM_CODE_START(ret_from_fork) +SYM_CODE_START(ret_from_fork_asm) call schedule_tail - beqz s0, 1f /* not from kernel thread */ - /* Call fn(arg) */ - move a0, s1 - jalr s0 -1: - move a0, sp /* pt_regs */ - call syscall_exit_to_user_mode + move a0, s1 /* fn */ + move a1, s0 /* fn_arg */ + move a2, sp /* pt_regs */ + call ret_from_fork j ret_from_exception -SYM_CODE_END(ret_from_fork) +SYM_CODE_END(ret_from_fork_asm) =20 #ifdef CONFIG_IRQ_STACKS /* diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 58b6482c2bf662bf5224ca50c8e21a68760a6b41..0d07e6d8f6b57beba438dbba5e8= c74a014582bee 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -17,7 +17,9 @@ #include #include #include +#include =20 +#include #include #include #include @@ -36,7 +38,7 @@ unsigned long __stack_chk_guard __read_mostly; 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Wed, 22 Jan 2025 14:56:57 -0800 (PST) Received: from charlie.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2f7e6aaf3b4sm2301375a91.25.2025.01.22.14.56.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jan 2025 14:56:56 -0800 (PST) From: Charlie Jenkins Date: Wed, 22 Jan 2025 14:56:21 -0800 Subject: [PATCH 2/4] riscv: entry: Split ret_from_fork() into user and kernel Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250122-riscv_optimize_entry-v1-2-4ee95559cfd0@rivosinc.com> References: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> In-Reply-To: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> To: Paul Walmsley , Palmer Dabbelt , Huacai Chen , WANG Xuerui , Thomas Gleixner , Peter Zijlstra , Andy Lutomirski , Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, Charlie Jenkins X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=4442; i=charlie@rivosinc.com; h=from:subject:message-id; bh=/8HxBSW4tXtNDNNcwvIlJWKmSet2jd64HJR1EYtmRzg=; b=owGbwMvMwCXWx5hUnlvL8Y3xtFoSQ/rE8i0b7c+0s/xcqt3/5b4w99KHFwsVdgnIyp27P0Uh+ PiLWpaFHaUsDGJcDLJiiiw81xqYW+/olx0VLZsAM4eVCWQIAxenAEzkvxojw/S94Wbr81rsm08G Ci0Pqo+N/Pys/vcCwWWTdNbd4dItesbwV/CvwkKz0Md8V+zighdYTl076b4Iy/KkostTt9bobnT +zwYA X-Developer-Key: i=charlie@rivosinc.com; a=openpgp; fpr=7D834FF11B1D8387E61C776FFB10D1F27D6B1354 This function was unified into a single function in commit ab9164dae273 ("riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork"). However that imposed a performance degradation. Partially reverting this commit to have ret_from_fork() split again results in a 1% increase on the number of times fork is able to be called per second. Signed-off-by: Charlie Jenkins --- arch/riscv/include/asm/asm-prototypes.h | 3 ++- arch/riscv/kernel/entry.S | 13 ++++++++++--- arch/riscv/kernel/process.c | 17 +++++++++++------ 3 files changed, 23 insertions(+), 10 deletions(-) diff --git a/arch/riscv/include/asm/asm-prototypes.h b/arch/riscv/include/a= sm/asm-prototypes.h index 733ff609778797001006c33bba9e3cc5b1f15387..bfc8ea5f9319b19449ec59493b4= 5b926df888832 100644 --- a/arch/riscv/include/asm/asm-prototypes.h +++ b/arch/riscv/include/asm/asm-prototypes.h @@ -52,7 +52,8 @@ DECLARE_DO_ERROR_INFO(do_trap_ecall_s); DECLARE_DO_ERROR_INFO(do_trap_ecall_m); DECLARE_DO_ERROR_INFO(do_trap_break); =20 -asmlinkage void ret_from_fork(void *fn_arg, int (*fn)(void *), struct pt_r= egs *regs); +asmlinkage void ret_from_fork_kernel(void *fn_arg, int (*fn)(void *), stru= ct pt_regs *regs); +asmlinkage void ret_from_fork_user(struct pt_regs *regs); asmlinkage void handle_bad_stack(struct pt_regs *regs); asmlinkage void do_page_fault(struct pt_regs *regs); asmlinkage void do_irq(struct pt_regs *regs); diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 9225c322279aa90e737b1d7144db084319cf8103..9386ef7444267f0b9bf8a0550f4= e31deaeb85881 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -319,14 +319,21 @@ SYM_CODE_END(handle_kernel_stack_overflow) ASM_NOKPROBE(handle_kernel_stack_overflow) #endif =20 -SYM_CODE_START(ret_from_fork_asm) +SYM_CODE_START(ret_from_fork_kernel_asm) call schedule_tail move a0, s1 /* fn */ move a1, s0 /* fn_arg */ move a2, sp /* pt_regs */ - call ret_from_fork + call ret_from_fork_kernel j ret_from_exception -SYM_CODE_END(ret_from_fork_asm) +SYM_CODE_END(ret_from_fork_kernel_asm) + +SYM_CODE_START(ret_from_fork_user_asm) + call schedule_tail + move a0, sp /* pt_regs */ + call ret_from_fork_user + j ret_from_exception +SYM_CODE_END(ret_from_fork_user_asm) =20 #ifdef CONFIG_IRQ_STACKS /* diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index 0d07e6d8f6b57beba438dbba5e8c74a014582bee..5f15236cb526bd9fe61636ed372= b4b76c94df946 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -38,7 +38,8 @@ unsigned long __stack_chk_guard __read_mostly; EXPORT_SYMBOL(__stack_chk_guard); #endif =20 -extern asmlinkage void ret_from_fork_asm(void); +extern asmlinkage void ret_from_fork_kernel_asm(void); +extern asmlinkage void ret_from_fork_user_asm(void); =20 void noinstr arch_cpu_idle(void) { @@ -208,14 +209,18 @@ int arch_dup_task_struct(struct task_struct *dst, str= uct task_struct *src) return 0; } =20 -asmlinkage void ret_from_fork(void *fn_arg, int (*fn)(void *), struct pt_r= egs *regs) +asmlinkage void ret_from_fork_kernel(void *fn_arg, int (*fn)(void *), stru= ct pt_regs *regs) { - if (unlikely(fn)) - fn(fn_arg); + fn(fn_arg); =20 syscall_exit_to_user_mode(regs); } =20 +asmlinkage void ret_from_fork_user(struct pt_regs *regs) +{ + syscall_exit_to_user_mode(regs); +} + int copy_thread(struct task_struct *p, const struct kernel_clone_args *arg= s) { unsigned long clone_flags =3D args->flags; @@ -238,6 +243,7 @@ int copy_thread(struct task_struct *p, const struct ker= nel_clone_args *args) =20 p->thread.s[0] =3D (unsigned long)args->fn; 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Wed, 22 Jan 2025 14:56:59 -0800 (PST) Received: from charlie.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2f7e6aaf3b4sm2301375a91.25.2025.01.22.14.56.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jan 2025 14:56:58 -0800 (PST) From: Charlie Jenkins Date: Wed, 22 Jan 2025 14:56:22 -0800 Subject: [PATCH 3/4] loongarch: entry: Migrate ret_from_fork() to C Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250122-riscv_optimize_entry-v1-3-4ee95559cfd0@rivosinc.com> References: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> In-Reply-To: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> To: Paul Walmsley , Palmer Dabbelt , Huacai Chen , WANG Xuerui , Thomas Gleixner , Peter Zijlstra , Andy Lutomirski , Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, Charlie Jenkins X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=5559; i=charlie@rivosinc.com; h=from:subject:message-id; bh=IfDjpWzOkJ2hu8S0SjhggOry7IIgS+knXj7qp/i1XMU=; b=owGbwMvMwCXWx5hUnlvL8Y3xtFoSQ/rE8i1dL+OOSYp8qL2mJrSGk+0H5+f2Kp+Pe9jq1j479 X6Zw93yjlIWBjEuBlkxRRaeaw3MrXf0y46Klk2AmcPKBDKEgYtTACbS58XwP8BkwY7+lm9r70p9 PBS5f82H6nUbnypMbNbf1X3B77b6BXlGhvWh9sl8e+4IHvqc9LB/msHdqb4Hds7b5PnpRYe+W/a WgzwA X-Developer-Key: i=charlie@rivosinc.com; a=openpgp; fpr=7D834FF11B1D8387E61C776FFB10D1F27D6B1354 Loongarch is the only architecture that calls syscall_exit_to_user_mode() from asm. Move the call into C so that this function can be inlined across all architectures. Signed-off-by: Charlie Jenkins --- arch/loongarch/include/asm/switch_to.h | 8 ++++++++ arch/loongarch/kernel/entry.S | 22 ++++++++++----------- arch/loongarch/kernel/process.c | 36 ++++++++++++++++++++++++++++--= ---- 3 files changed, 48 insertions(+), 18 deletions(-) diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/includ= e/asm/switch_to.h index 5b225aff3ba21aa06d0713bc8e73e1b941389630..a1c5576f1fd145670e13038bec6= dd390486099ab 100644 --- a/arch/loongarch/include/asm/switch_to.h +++ b/arch/loongarch/include/asm/switch_to.h @@ -26,6 +26,14 @@ extern asmlinkage struct task_struct *__switch_to(struct= task_struct *prev, struct task_struct *next, struct thread_info *next_ti, void *sched_ra, void *sched_cfa); =20 +void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struc= t *prev, + struct pt_regs *regs, + int (*fn)(void *), + void *fn_arg); + +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, + struct pt_regs *regs); + /* * For newly created kernel threads switch_to() will return to * ret_from_kernel_thread, newly created user threads to ret_from_fork. diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S index 48e7e34e355e83eae8165957ba2eac05a8bf17df..2abc29e573810e000f2fef4646d= dca0dbb80eabe 100644 --- a/arch/loongarch/kernel/entry.S +++ b/arch/loongarch/kernel/entry.S @@ -77,24 +77,22 @@ SYM_CODE_START(handle_syscall) SYM_CODE_END(handle_syscall) _ASM_NOKPROBE(handle_syscall) =20 -SYM_CODE_START(ret_from_fork) +SYM_CODE_START(ret_from_fork_asm) UNWIND_HINT_REGS - bl schedule_tail # a0 =3D struct task_struct *prev - move a0, sp - bl syscall_exit_to_user_mode + move a1, sp + bl ret_from_fork RESTORE_STATIC RESTORE_SOME RESTORE_SP_AND_RET -SYM_CODE_END(ret_from_fork) +SYM_CODE_END(ret_from_fork_asm) =20 -SYM_CODE_START(ret_from_kernel_thread) +SYM_CODE_START(ret_from_kernel_thread_asm) UNWIND_HINT_REGS - bl schedule_tail # a0 =3D struct task_struct *prev - move a0, s1 - jirl ra, s0, 0 - move a0, sp - bl syscall_exit_to_user_mode + move a1, sp + move a2, s0 + move a3, s1 + bl ret_from_kernel_thread RESTORE_STATIC RESTORE_SOME RESTORE_SP_AND_RET -SYM_CODE_END(ret_from_kernel_thread) +SYM_CODE_END(ret_from_kernel_thread_asm) diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/proces= s.c index 6e58f65455c7ca3eae2e88ed852c8655a6701e5c..9bb069ef363fefed1f2115e6572= b31c2b76bb414 100644 --- a/arch/loongarch/kernel/process.c +++ b/arch/loongarch/kernel/process.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -47,6 +48,7 @@ #include #include #include +#include #include #include =20 @@ -63,8 +65,12 @@ EXPORT_SYMBOL(__stack_chk_guard); unsigned long boot_option_idle_override =3D IDLE_NO_OVERRIDE; EXPORT_SYMBOL(boot_option_idle_override); =20 -asmlinkage void ret_from_fork(void); -asmlinkage void ret_from_kernel_thread(void); +asmlinkage void restore_and_ret(void); +asmlinkage void ret_from_fork_asm(void); +void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struc= t *prev, + struct pt_regs *regs, + int (*fn)(void *), + void *fn_arg) =20 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) { @@ -138,6 +144,24 @@ int arch_dup_task_struct(struct task_struct *dst, stru= ct task_struct *src) return 0; } =20 +void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struc= t *prev, + struct pt_regs *regs, + int (*fn)(void *), + void *fn_arg) +{ + schedule_tail(prev); + + fn(fn_arg); + + syscall_exit_to_user_mode(regs); +} + +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, = struct pt_regs *regs) +{ + schedule_tail(prev); + syscall_exit_to_user_mode(regs); +} + /* * Copy architecture-specific thread state */ @@ -165,8 +189,8 @@ int copy_thread(struct task_struct *p, const struct ker= nel_clone_args *args) p->thread.reg03 =3D childksp; p->thread.reg23 =3D (unsigned long)args->fn; p->thread.reg24 =3D (unsigned long)args->fn_arg; - p->thread.reg01 =3D (unsigned long)ret_from_kernel_thread; - p->thread.sched_ra =3D (unsigned long)ret_from_kernel_thread; + p->thread.reg01 =3D (unsigned long)ret_from_kernel_thread_asm; + p->thread.sched_ra =3D (unsigned long)ret_from_kernel_thread_asm; memset(childregs, 0, sizeof(struct pt_regs)); childregs->csr_euen =3D p->thread.csr_euen; childregs->csr_crmd =3D p->thread.csr_crmd; @@ -182,8 +206,8 @@ int copy_thread(struct task_struct *p, const struct ker= nel_clone_args *args) childregs->regs[3] =3D usp; =20 p->thread.reg03 =3D (unsigned long) childregs; - p->thread.reg01 =3D (unsigned long) ret_from_fork; - p->thread.sched_ra =3D (unsigned long) ret_from_fork; + p->thread.reg01 =3D (unsigned long) ret_from_fork_asm; + p->thread.sched_ra =3D (unsigned long) ret_from_fork_asm; =20 /* * New tasks lose permission to use the fpu. 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Wed, 22 Jan 2025 14:56:59 -0800 (PST) From: Charlie Jenkins Date: Wed, 22 Jan 2025 14:56:23 -0800 Subject: [PATCH 4/4] entry: Inline syscall_exit_to_user_mode() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250122-riscv_optimize_entry-v1-4-4ee95559cfd0@rivosinc.com> References: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> In-Reply-To: <20250122-riscv_optimize_entry-v1-0-4ee95559cfd0@rivosinc.com> To: Paul Walmsley , Palmer Dabbelt , Huacai Chen , WANG Xuerui , Thomas Gleixner , Peter Zijlstra , Andy Lutomirski , Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, Charlie Jenkins X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=5140; i=charlie@rivosinc.com; h=from:subject:message-id; bh=Z1tS2IEfH8NjFHjnsgjlU412ZTPZo9IgZRJ3cE9Ze5k=; b=owGbwMvMwCXWx5hUnlvL8Y3xtFoSQ/rE8i1Xrbq3yFk9XtolEHc+YPPKS4zHdLyPbp1l/T3K8 ibjJu3nHaUsDGJcDLJiiiw81xqYW+/olx0VLZsAM4eVCWQIAxenAExEo4mR4cTqzcKbngRY/JjW 1KZ9LnmP/3vOqTsu/eEzCLYLaWh9uJbhr5xYRZ/aZPPgR5fkV/YHnnWcJf2O39WubLv+9xcTFs2 W4QIA X-Developer-Key: i=charlie@rivosinc.com; a=openpgp; fpr=7D834FF11B1D8387E61C776FFB10D1F27D6B1354 Architectures using the generic entry code can be optimized by having syscall_exit_to_user_mode inlined. Signed-off-by: Charlie Jenkins --- include/linux/entry-common.h | 43 ++++++++++++++++++++++++++++++++++++-- kernel/entry/common.c | 49 +---------------------------------------= ---- 2 files changed, 42 insertions(+), 50 deletions(-) diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index fc61d0205c97084acc89c8e45e088946f5e6d9b2..a46861ffd6858fadf4014c387e8= f2f216a879c25 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -14,6 +14,7 @@ #include =20 #include +#include =20 /* * Define dummy _TIF work flags if not defined by the architecture or for @@ -366,6 +367,15 @@ static __always_inline void exit_to_user_mode(void) lockdep_hardirqs_on(CALLER_ADDR0); } =20 +/** + * syscall_exit_work - Handle work before returning to user mode + * @regs: Pointer to current pt_regs + * @work: Current thread syscall work + * + * Do one-time syscall specific work. + */ +void syscall_exit_work(struct pt_regs *regs, unsigned long work); + /** * syscall_exit_to_user_mode_work - Handle work before returning to user m= ode * @regs: Pointer to currents pt_regs @@ -379,7 +389,30 @@ static __always_inline void exit_to_user_mode(void) * make the final state transitions. Interrupts must stay disabled between * return from this function and the invocation of exit_to_user_mode(). */ -void syscall_exit_to_user_mode_work(struct pt_regs *regs); +static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs = *regs) +{ + unsigned long work =3D READ_ONCE(current_thread_info()->syscall_work); + unsigned long nr =3D syscall_get_nr(current, regs); + + CT_WARN_ON(ct_state() !=3D CONTEXT_KERNEL); + + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr)) + local_irq_enable(); + } + + rseq_syscall(regs); + + /* + * Do one-time syscall specific work. If these work items are + * enabled, we want to run them exactly once per syscall exit with + * interrupts enabled. + */ + if (unlikely(work & SYSCALL_WORK_EXIT)) + syscall_exit_work(regs, work); + local_irq_disable_exit_to_user(); + exit_to_user_mode_prepare(regs); +} =20 /** * syscall_exit_to_user_mode - Handle work before returning to user mode @@ -410,7 +443,13 @@ void syscall_exit_to_user_mode_work(struct pt_regs *re= gs); * exit_to_user_mode(). This function is preferred unless there is a * compelling architectural reason to use the separate functions. */ -void syscall_exit_to_user_mode(struct pt_regs *regs); +static __always_inline void syscall_exit_to_user_mode(struct pt_regs *regs) +{ + instrumentation_begin(); + syscall_exit_to_user_mode_work(regs); + instrumentation_end(); + exit_to_user_mode(); +} =20 /** * irqentry_enter_from_user_mode - Establish state before invoking the irq= handler diff --git a/kernel/entry/common.c b/kernel/entry/common.c index e33691d5adf7aab4af54cf2bf8e5ef5bd6ad1424..f55e421fb196dd5f9d4e34dd85a= e096c774cf879 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -146,7 +146,7 @@ static inline bool report_single_step(unsigned long wor= k) return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP; } =20 -static void syscall_exit_work(struct pt_regs *regs, unsigned long work) +void syscall_exit_work(struct pt_regs *regs, unsigned long work) { bool step; =20 @@ -173,53 +173,6 @@ static void syscall_exit_work(struct pt_regs *regs, un= signed long work) ptrace_report_syscall_exit(regs, step); } =20 -/* - * Syscall specific exit to user mode preparation. Runs with interrupts - * enabled. - */ -static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) -{ - unsigned long work =3D READ_ONCE(current_thread_info()->syscall_work); - unsigned long nr =3D syscall_get_nr(current, regs); - - CT_WARN_ON(ct_state() !=3D CT_STATE_KERNEL); - - if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { - if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr)) - local_irq_enable(); - } - - rseq_syscall(regs); - - /* - * Do one-time syscall specific work. If these work items are - * enabled, we want to run them exactly once per syscall exit with - * interrupts enabled. - */ - if (unlikely(work & SYSCALL_WORK_EXIT)) - syscall_exit_work(regs, work); -} - -static __always_inline void __syscall_exit_to_user_mode_work(struct pt_reg= s *regs) -{ - syscall_exit_to_user_mode_prepare(regs); - local_irq_disable_exit_to_user(); - exit_to_user_mode_prepare(regs); -} - -void syscall_exit_to_user_mode_work(struct pt_regs *regs) -{ - __syscall_exit_to_user_mode_work(regs); -} - -__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs) -{ - instrumentation_begin(); - __syscall_exit_to_user_mode_work(regs); - instrumentation_end(); - exit_to_user_mode(); -} - noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs) { enter_from_user_mode(regs); --=20 2.43.0