| Message ID | 20240201174103.798138-1-adhemerval.zanella@linaro.org |
|---|---|
| State | Accepted |
| Commit | bbd248ac0d75efdef8fe61ea69b1fb25fb95b6e7 |
| Headers | show |
| Series | mips: FIx clone3 implementation (BZ 31325) | expand |
On Thu, Feb 1, 2024 at 9:41 AM Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote: > > For o32 we need to setup a minimal stack frame to allow cprestore > on __thread_start_clone3 (which instruct the linker to save the > gp for PIC). Also, there is no guarantee by kABI that $8 will be > preserved after syscall execution, so we need to save it on the > provided stack. > > Checked on mipsel-linux-gnu. works ok on yocto reference mips ( Big-endian ) ( mips-linux-gnu ) Tested-by: Khem Raj <raj.khem@gmail.com> > > Reported-by: Khem Raj <raj.khem@gmail.com> > --- > sysdeps/unix/sysv/linux/mips/clone3.S | 32 ++++++++++++++++++++++----- > 1 file changed, 27 insertions(+), 5 deletions(-) > > diff --git a/sysdeps/unix/sysv/linux/mips/clone3.S b/sysdeps/unix/sysv/linux/mips/clone3.S > index e9fec2fa47..481b8ae963 100644 > --- a/sysdeps/unix/sysv/linux/mips/clone3.S > +++ b/sysdeps/unix/sysv/linux/mips/clone3.S > @@ -37,11 +37,6 @@ > > .text > .set nomips16 > -#if _MIPS_SIM == _ABIO32 > -# define EXTRA_LOCALS 1 > -#else > -# define EXTRA_LOCALS 0 > -#endif > #define FRAMESZ ((NARGSAVE*SZREG)+ALSZ)&ALMASK > GPOFF= FRAMESZ-(1*SZREG) > NESTED(__clone3, SZREG, sp) > @@ -68,8 +63,31 @@ NESTED(__clone3, SZREG, sp) > beqz a0, L(error) /* No NULL cl_args pointer. */ > beqz a2, L(error) /* No NULL function pointer. */ > > +#if _MIPS_SIM == _ABIO32 > + /* Both stack and stack_size on clone_args are defined as uint64_t, and > + there is no need to handle values larger than to 32 bits for o32. */ > +# if __BYTE_ORDER == __BIG_ENDIAN > +# define CL_STACKPOINTER_OFFSET 44 > +# define CL_STACKSIZE_OFFSET 52 > +# else > +# define CL_STACKPOINTER_OFFSET 40 > +# define CL_STACKSIZE_OFFSET 48 > +# endif > + > + /* For o32 we need to setup a minimal stack frame to allow cprestore > + on __thread_start_clone3. Also there is no guarantee by kABI that > + $8 will be preserved after syscall execution (so we need to save it > + on the provided stack). */ > + lw t0, CL_STACKPOINTER_OFFSET(a0) /* Load the stack pointer. */ > + lw t1, CL_STACKSIZE_OFFSET(a0) /* Load the stack_size. */ > + addiu t1, -32 /* Update the stack size. */ > + addu t2, t1, t0 /* Calculate the thread stack. */ > + sw a3, 0(t2) /* Save argument pointer. */ > + sw t1, CL_STACKSIZE_OFFSET(a0) /* Save the new stack size. */ > +#else > move $8, a3 /* a3 is set to 0/1 for syscall success/error > while a4/$8 is returned unmodified. */ > +#endif > > /* Do the system call, the kernel expects: > v0: system call number > @@ -125,7 +143,11 @@ L(thread_start_clone3): > > /* Restore the arg for user's function. */ > move t9, a2 /* Function pointer. */ > +#if _MIPS_SIM == _ABIO32 > + PTR_L a0, 0(sp) > +#else > move a0, $8 /* Argument pointer. */ > +#endif > > /* Call the user's function. */ > jal t9 > -- > 2.34.1 >
On 01/02/24 21:06, Khem Raj wrote: > On Thu, Feb 1, 2024 at 9:41 AM Adhemerval Zanella > <adhemerval.zanella@linaro.org> wrote: >> >> For o32 we need to setup a minimal stack frame to allow cprestore >> on __thread_start_clone3 (which instruct the linker to save the >> gp for PIC). Also, there is no guarantee by kABI that $8 will be >> preserved after syscall execution, so we need to save it on the >> provided stack. >> >> Checked on mipsel-linux-gnu. > > works ok on yocto reference mips ( Big-endian ) ( mips-linux-gnu ) > > Tested-by: Khem Raj <raj.khem@gmail.com> Thanks, I will install it.
diff --git a/sysdeps/unix/sysv/linux/mips/clone3.S b/sysdeps/unix/sysv/linux/mips/clone3.S index e9fec2fa47..481b8ae963 100644 --- a/sysdeps/unix/sysv/linux/mips/clone3.S +++ b/sysdeps/unix/sysv/linux/mips/clone3.S @@ -37,11 +37,6 @@ .text .set nomips16 -#if _MIPS_SIM == _ABIO32 -# define EXTRA_LOCALS 1 -#else -# define EXTRA_LOCALS 0 -#endif #define FRAMESZ ((NARGSAVE*SZREG)+ALSZ)&ALMASK GPOFF= FRAMESZ-(1*SZREG) NESTED(__clone3, SZREG, sp) @@ -68,8 +63,31 @@ NESTED(__clone3, SZREG, sp) beqz a0, L(error) /* No NULL cl_args pointer. */ beqz a2, L(error) /* No NULL function pointer. */ +#if _MIPS_SIM == _ABIO32 + /* Both stack and stack_size on clone_args are defined as uint64_t, and + there is no need to handle values larger than to 32 bits for o32. */ +# if __BYTE_ORDER == __BIG_ENDIAN +# define CL_STACKPOINTER_OFFSET 44 +# define CL_STACKSIZE_OFFSET 52 +# else +# define CL_STACKPOINTER_OFFSET 40 +# define CL_STACKSIZE_OFFSET 48 +# endif + + /* For o32 we need to setup a minimal stack frame to allow cprestore + on __thread_start_clone3. Also there is no guarantee by kABI that + $8 will be preserved after syscall execution (so we need to save it + on the provided stack). */ + lw t0, CL_STACKPOINTER_OFFSET(a0) /* Load the stack pointer. */ + lw t1, CL_STACKSIZE_OFFSET(a0) /* Load the stack_size. */ + addiu t1, -32 /* Update the stack size. */ + addu t2, t1, t0 /* Calculate the thread stack. */ + sw a3, 0(t2) /* Save argument pointer. */ + sw t1, CL_STACKSIZE_OFFSET(a0) /* Save the new stack size. */ +#else move $8, a3 /* a3 is set to 0/1 for syscall success/error while a4/$8 is returned unmodified. */ +#endif /* Do the system call, the kernel expects: v0: system call number @@ -125,7 +143,11 @@ L(thread_start_clone3): /* Restore the arg for user's function. */ move t9, a2 /* Function pointer. */ +#if _MIPS_SIM == _ABIO32 + PTR_L a0, 0(sp) +#else move a0, $8 /* Argument pointer. */ +#endif /* Call the user's function. */ jal t9