[RFC v8 05/20] um: extend arch_switch_to for alternate SUBARCH
From: Hajime Tazaki <hidden>
Date: 2021-01-20 03:47:02
Also in:
linux-um
Subsystem:
ptrace support, the rest, user-mode linux (uml), x86 architecture (32-bit and 64-bit) · Maintainers:
Oleg Nesterov, Linus Torvalds, Richard Weinberger, Anton Ivanov, Johannes Berg, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
This commit introduces additional argument of previous task when context switch happens. New SUBARCH can use the new information to switch tasks in a subarch-specific manner. The patch is particularly required by library mode, implemented as a SUBARCH of UML. Having access to the previous thread will be required in the library mode for it to implement thread switching correctly. Signed-off-by: Hajime Tazaki <redacted> --- arch/um/kernel/process.c | 6 +++--- arch/x86/um/ptrace_32.c | 2 +- arch/x86/um/syscalls_64.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 2a986ece5478..9b0a36f64339 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c@@ -83,7 +83,7 @@ static inline void set_current(struct task_struct *task) { external_pid(), task }); } -extern void arch_switch_to(struct task_struct *to); +extern void arch_switch_to(struct task_struct *from, struct task_struct *to); void *__switch_to(struct task_struct *from, struct task_struct *to) {
@@ -91,7 +91,7 @@ void *__switch_to(struct task_struct *from, struct task_struct *to) set_current(to); switch_threads(&from->thread.switch_buf, &to->thread.switch_buf); - arch_switch_to(current); + arch_switch_to(from, to); return current->thread.prev_sched; }
@@ -149,7 +149,7 @@ void fork_handler(void) * arch_switch_to isn't needed. We could want to apply this to * improve performance. -bb */ - arch_switch_to(current); + arch_switch_to(NULL, current); current->thread.prev_sched = NULL;
diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c
index 2497bac56066..0f184710d4ca 100644
--- a/arch/x86/um/ptrace_32.c
+++ b/arch/x86/um/ptrace_32.c@@ -11,7 +11,7 @@ extern int arch_switch_tls(struct task_struct *to); -void arch_switch_to(struct task_struct *to) +void arch_switch_to(struct task_struct *from, struct task_struct *to) { int err = arch_switch_tls(to); if (!err)
diff --git a/arch/x86/um/syscalls_64.c b/arch/x86/um/syscalls_64.c
index 58f51667e2e4..2ef9474d2bd2 100644
--- a/arch/x86/um/syscalls_64.c
+++ b/arch/x86/um/syscalls_64.c@@ -80,7 +80,7 @@ SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2) return arch_prctl(current, option, (unsigned long __user *) arg2); } -void arch_switch_to(struct task_struct *to) +void arch_switch_to(struct task_struct *from, struct task_struct *to) { if ((to->thread.arch.fs == 0) || (to->mm == NULL)) return;
--
2.21.0 (Apple Git-122.2)