| Message ID | 20250122-riscv_optimize_entry-v1-4-4ee95559cfd0@rivosinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | entry: Move ret_from_fork() to C and inline syscall_exit_to_user_mode() | expand |
Hi Charlie, kernel test robot noticed the following build errors: [auto build test ERROR on ffd294d346d185b70e28b1a28abe367bbfe53c04] url: https://github.com/intel-lab-lkp/linux/commits/Charlie-Jenkins/riscv-entry-Convert-ret_from_fork-to-C/20250123-065957 base: ffd294d346d185b70e28b1a28abe367bbfe53c04 patch link: https://lore.kernel.org/r/20250122-riscv_optimize_entry-v1-4-4ee95559cfd0%40rivosinc.com patch subject: [PATCH 4/4] entry: Inline syscall_exit_to_user_mode() config: x86_64-randconfig-071-20250123 (https://download.01.org/0day-ci/archive/20250124/202501240036.hxoscXJM-lkp@intel.com/config) compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250124/202501240036.hxoscXJM-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202501240036.hxoscXJM-lkp@intel.com/ All errors (new ones prefixed by >>): In file included from arch/x86/kernel/ptrace.c:40: In file included from arch/x86/include/asm/traps.h:9: In file included from arch/x86/include/asm/idtentry.h:11: >> include/linux/entry-common.h:397:27: error: use of undeclared identifier 'CONTEXT_KERNEL' 397 | CT_WARN_ON(ct_state() != CONTEXT_KERNEL); | ^ 1 error generated. vim +/CONTEXT_KERNEL +397 include/linux/entry-common.h 378 379 /** 380 * syscall_exit_to_user_mode_work - Handle work before returning to user mode 381 * @regs: Pointer to currents pt_regs 382 * 383 * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling 384 * exit_to_user_mode() to perform the final transition to user mode. 385 * 386 * Calling convention is the same as for syscall_exit_to_user_mode() and it 387 * returns with all work handled and interrupts disabled. The caller must 388 * invoke exit_to_user_mode() before actually switching to user mode to 389 * make the final state transitions. Interrupts must stay disabled between 390 * return from this function and the invocation of exit_to_user_mode(). 391 */ 392 static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) 393 { 394 unsigned long work = READ_ONCE(current_thread_info()->syscall_work); 395 unsigned long nr = syscall_get_nr(current, regs); 396 > 397 CT_WARN_ON(ct_state() != CONTEXT_KERNEL); 398 399 if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { 400 if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr)) 401 local_irq_enable(); 402 } 403 404 rseq_syscall(regs); 405 406 /* 407 * Do one-time syscall specific work. If these work items are 408 * enabled, we want to run them exactly once per syscall exit with 409 * interrupts enabled. 410 */ 411 if (unlikely(work & SYSCALL_WORK_EXIT)) 412 syscall_exit_work(regs, work); 413 local_irq_disable_exit_to_user(); 414 exit_to_user_mode_prepare(regs); 415 } 416
Hi Charlie,
kernel test robot noticed the following build errors:
[auto build test ERROR on ffd294d346d185b70e28b1a28abe367bbfe53c04]
url: https://github.com/intel-lab-lkp/linux/commits/Charlie-Jenkins/riscv-entry-Convert-ret_from_fork-to-C/20250123-065957
base: ffd294d346d185b70e28b1a28abe367bbfe53c04
patch link: https://lore.kernel.org/r/20250122-riscv_optimize_entry-v1-4-4ee95559cfd0%40rivosinc.com
patch subject: [PATCH 4/4] entry: Inline syscall_exit_to_user_mode()
config: x86_64-randconfig-072-20250123 (https://download.01.org/0day-ci/archive/20250124/202501240101.mSdGpEoH-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250124/202501240101.mSdGpEoH-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501240101.mSdGpEoH-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from arch/x86/include/asm/bug.h:99,
from include/linux/bug.h:5,
from include/linux/thread_info.h:13,
from include/linux/sched.h:14,
from arch/x86/mm/fault.c:7:
include/linux/entry-common.h: In function 'syscall_exit_to_user_mode_work':
>> include/linux/entry-common.h:397:34: error: 'CONTEXT_KERNEL' undeclared (first use in this function); did you mean 'PERF_CONTEXT_KERNEL'?
397 | CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
| ^~~~~~~~~~~~~~
include/asm-generic/bug.h:123:32: note: in definition of macro 'WARN_ON'
123 | int __ret_warn_on = !!(condition); \
| ^~~~~~~~~
include/linux/entry-common.h:397:9: note: in expansion of macro 'CT_WARN_ON'
397 | CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
| ^~~~~~~~~~
include/linux/entry-common.h:397:34: note: each undeclared identifier is reported only once for each function it appears in
397 | CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
| ^~~~~~~~~~~~~~
include/asm-generic/bug.h:123:32: note: in definition of macro 'WARN_ON'
123 | int __ret_warn_on = !!(condition); \
| ^~~~~~~~~
include/linux/entry-common.h:397:9: note: in expansion of macro 'CT_WARN_ON'
397 | CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
| ^~~~~~~~~~
vim +397 include/linux/entry-common.h
378
379 /**
380 * syscall_exit_to_user_mode_work - Handle work before returning to user mode
381 * @regs: Pointer to currents pt_regs
382 *
383 * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling
384 * exit_to_user_mode() to perform the final transition to user mode.
385 *
386 * Calling convention is the same as for syscall_exit_to_user_mode() and it
387 * returns with all work handled and interrupts disabled. The caller must
388 * invoke exit_to_user_mode() before actually switching to user mode to
389 * make the final state transitions. Interrupts must stay disabled between
390 * return from this function and the invocation of exit_to_user_mode().
391 */
392 static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
393 {
394 unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
395 unsigned long nr = syscall_get_nr(current, regs);
396
> 397 CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
398
399 if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
400 if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr))
401 local_irq_enable();
402 }
403
404 rseq_syscall(regs);
405
406 /*
407 * Do one-time syscall specific work. If these work items are
408 * enabled, we want to run them exactly once per syscall exit with
409 * interrupts enabled.
410 */
411 if (unlikely(work & SYSCALL_WORK_EXIT))
412 syscall_exit_work(regs, work);
413 local_irq_disable_exit_to_user();
414 exit_to_user_mode_prepare(regs);
415 }
416
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index fc61d0205c97084acc89c8e45e088946f5e6d9b2..a46861ffd6858fadf4014c387e8f2f216a879c25 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -14,6 +14,7 @@ #include <linux/kmsan.h> #include <asm/entry-common.h> +#include <asm/syscall.h> /* * 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); } +/** + * 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 mode * @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 = READ_ONCE(current_thread_info()->syscall_work); + unsigned long nr = syscall_get_nr(current, regs); + + CT_WARN_ON(ct_state() != 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); +} /** * 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 *regs); * 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(); +} /** * 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..f55e421fb196dd5f9d4e34dd85ae096c774cf879 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -146,7 +146,7 @@ static inline bool report_single_step(unsigned long work) return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP; } -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; @@ -173,53 +173,6 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long work) ptrace_report_syscall_exit(regs, step); } -/* - * 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 = READ_ONCE(current_thread_info()->syscall_work); - unsigned long nr = syscall_get_nr(current, regs); - - CT_WARN_ON(ct_state() != 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_regs *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);
Architectures using the generic entry code can be optimized by having syscall_exit_to_user_mode inlined. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- include/linux/entry-common.h | 43 ++++++++++++++++++++++++++++++++++++-- kernel/entry/common.c | 49 +------------------------------------------- 2 files changed, 42 insertions(+), 50 deletions(-)