Messages in this thread Patch in this message | | | From | Guoyun Sun <> | Subject | [PATCH] MIPS: Add get_thread_area syscall | Date | Fri, 13 Dec 2019 14:15:05 +0800 |
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CRIU(https://criu.org/) tools will dump TLS(Thread Local Storage) by get_thread_area during checkpoint and restore TLS by set_thread_area during restore. without syscall get_thread_area, criu restore will fail on MIPS platform.because a variable with GCC __thread is invalid.
The following function will be called when criu restore
static inline void restore_tls(tls_t *ptls) { asm volatile( "move $4, %0 \n" "li $2, "__stringify(__NR_set_thread_area)" \n" "syscall \n" : : "r"(*ptls) : "$4","$2","memory");
With this patch, the *ptls can be obtained by get_thread_area on MIPS platform when criu checkpoint. just like this:
static inline void arch_get_tls(tls_t *ptls) { asm volatile( "move $4, %0 \n" "li $2, "__stringify(__NR_get_thread_area)" \n" "syscall \n" : : "r"(ptls) : "$4","$2","memory");
}
Signed-off-by: Guoyun Sun <sunguoyun@loongson.cn> --- arch/mips/kernel/syscall.c | 10 ++++++++++ arch/mips/kernel/syscalls/syscall_n32.tbl | 1 + arch/mips/kernel/syscalls/syscall_n64.tbl | 1 + arch/mips/kernel/syscalls/syscall_o32.tbl | 1 + 4 files changed, 13 insertions(+)
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c index c333e57..20bf4c5 100644 --- a/arch/mips/kernel/syscall.c +++ b/arch/mips/kernel/syscall.c @@ -94,6 +94,16 @@ SYSCALL_DEFINE1(set_thread_area, unsigned long, addr) return 0; } +SYSCALL_DEFINE1(get_thread_area, unsigned long __user *, u_info) +{ + struct thread_info *ti = task_thread_info(current); + + if (copy_to_user(u_info, &(ti->tp_value), sizeof(ti->tp_value))) + return -EFAULT; + + return 0; +} + static inline int mips_atomic_set(unsigned long addr, unsigned long new) { unsigned long old, tmp; diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index e7c5ab3..7da83d0 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -374,3 +374,4 @@ 433 n32 fspick sys_fspick 434 n32 pidfd_open sys_pidfd_open 435 n32 clone3 __sys_clone3 +436 n32 get_thread_area sys_get_thread_area diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl index 13cd665..4f04bf0 100644 --- a/arch/mips/kernel/syscalls/syscall_n64.tbl +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl @@ -350,3 +350,4 @@ 433 n64 fspick sys_fspick 434 n64 pidfd_open sys_pidfd_open 435 n64 clone3 __sys_clone3 +436 n64 get_thread_area sys_get_thread_area diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index 353539e..9d79abe 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -423,3 +423,4 @@ 433 o32 fspick sys_fspick 434 o32 pidfd_open sys_pidfd_open 435 o32 clone3 __sys_clone3 +436 o32 get_thread_area sys_get_thread_area -- 2.1.0
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