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hexagon: kernel_thread()/kernel_execve() conversion
introduce sane current_pt_regs(), use it in syscalls where needed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
parent
ddffeb8c4d
commit
9952185554
7 changed files with 46 additions and 98 deletions
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@ -31,6 +31,8 @@ config HEXAGON
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select GENERIC_CLOCKEVENTS
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select GENERIC_CLOCKEVENTS_BROADCAST
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select MODULES_USE_ELF_RELA
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select GENERIC_KERNEL_THREAD
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select GENERIC_KERNEL_EXECVE
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---help---
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Qualcomm Hexagon is a processor architecture designed for high
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performance and low power across a wide variety of applications.
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@ -34,7 +34,6 @@
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struct task_struct;
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/* this is defined in arch/process.c */
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extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
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extern unsigned long thread_saved_pc(struct task_struct *tsk);
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extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
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@ -32,4 +32,8 @@
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extern int regs_query_register_offset(const char *name);
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extern const char *regs_query_register_name(unsigned int offset);
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#define current_pt_regs() \
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((struct pt_regs *) \
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((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
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#endif
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@ -25,33 +25,6 @@
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#include <linux/uaccess.h>
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#include <linux/slab.h>
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/*
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* Kernel thread creation. The desired kernel function is "wrapped"
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* in the kernel_thread_helper function, which does cleanup
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* afterwards.
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*/
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static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
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{
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do_exit(fn(arg));
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}
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int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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/*
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* Yes, we're exploting illicit knowledge of the ABI here.
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*/
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regs.r00 = (unsigned long) arg;
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regs.r01 = (unsigned long) fn;
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pt_set_elr(®s, (unsigned long)kernel_thread_helper);
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pt_set_kmode(®s);
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return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
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}
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EXPORT_SYMBOL(kernel_thread);
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/*
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* Program thread launch. Often defined as a macro in processor.h,
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* but we're shooting for a small footprint and it's not an inner-loop
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@ -114,7 +87,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
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* Copy architecture-specific thread state
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*/
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int copy_thread(unsigned long clone_flags, unsigned long usp,
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unsigned long unused, struct task_struct *p,
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unsigned long arg, struct task_struct *p,
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struct pt_regs *regs)
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{
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struct thread_info *ti = task_thread_info(p);
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@ -125,19 +98,28 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
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childregs = (struct pt_regs *) (((unsigned long) ti + THREAD_SIZE) -
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sizeof(*childregs));
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memcpy(childregs, regs, sizeof(*childregs));
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ti->regs = childregs;
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/*
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* Establish kernel stack pointer and initial PC for new thread
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* Note that unlike the usual situation, we do not copy the
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* parent's callee-saved here; those are in pt_regs and whatever
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* we leave here will be overridden on return to userland.
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*/
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ss = (struct hexagon_switch_stack *) ((unsigned long) childregs -
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sizeof(*ss));
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ss->lr = (unsigned long)ret_from_fork;
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p->thread.switch_sp = ss;
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if (unlikely(p->flags & PF_KTHREAD)) {
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memset(childregs, 0, sizeof(struct pt_regs));
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/* r24 <- fn, r25 <- arg */
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ss->r2524 = usp | ((u64)arg << 32);
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pt_set_kmode(childregs);
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return 0;
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}
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memcpy(childregs, regs, sizeof(*childregs));
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ss->r2524 = 0;
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/* If User mode thread, set pt_reg stack pointer as per parameter */
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if (user_mode(childregs)) {
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pt_set_rte_sp(childregs, usp);
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/* Child sees zero return value */
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@ -160,26 +142,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
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* this point in the fork process
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* Might also want to set things like ti->addr_limit
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*/
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} else {
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/*
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* If kernel thread, resume stack is kernel stack base.
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* Note that this is pointer arithmetic on pt_regs *
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*/
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pt_set_rte_sp(childregs, (unsigned long)(childregs + 1));
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/*
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* We need the current thread_info fast path pointer
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* set up in pt_regs. The register to be used is
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* parametric for assembler code, but the mechanism
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* doesn't drop neatly into C. Needs to be fixed.
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*/
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childregs->THREADINFO_REG = (unsigned long) ti;
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}
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/*
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* thread_info pointer is pulled out of task_struct "stack"
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* field on switch_to.
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*/
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p->stack = (void *)ti;
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return 0;
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}
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@ -249,14 +249,14 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
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*/
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asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
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{
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struct pt_regs *regs = current_thread_info()->regs;
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struct pt_regs *regs = current_pt_regs();
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return do_sigaltstack(uss, uoss, regs->r29);
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}
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asmlinkage int sys_rt_sigreturn(void)
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{
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struct pt_regs *regs = current_thread_info()->regs;
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struct pt_regs *regs = current_pt_regs();
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struct rt_sigframe __user *frame;
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sigset_t blocked;
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@ -39,7 +39,7 @@ asmlinkage int sys_execve(char __user *ufilename,
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const char __user *const __user *argv,
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const char __user *const __user *envp)
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{
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struct pt_regs *pregs = current_thread_info()->regs;
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struct pt_regs *pregs = current_pt_regs();
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struct filename *filename;
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int retval;
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@ -57,33 +57,10 @@ asmlinkage int sys_execve(char __user *ufilename,
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asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
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unsigned long parent_tidp, unsigned long child_tidp)
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{
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struct pt_regs *pregs = current_thread_info()->regs;
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struct pt_regs *pregs = current_pt_regs();
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if (!newsp)
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newsp = pregs->SP;
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return do_fork(clone_flags, newsp, pregs, 0, (int __user *)parent_tidp,
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(int __user *)child_tidp);
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}
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/*
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* Do a system call from the kernel, so as to have a proper pt_regs
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* and recycle the sys_execvpe infrustructure.
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*/
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int kernel_execve(const char *filename,
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const char *const argv[], const char *const envp[])
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{
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register unsigned long __a0 asm("r0") = (unsigned long) filename;
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register unsigned long __a1 asm("r1") = (unsigned long) argv;
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register unsigned long __a2 asm("r2") = (unsigned long) envp;
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int retval;
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__asm__ volatile(
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" R6 = #%4;\n"
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" trap0(#1);\n"
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" %0 = R0;\n"
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: "=r" (retval)
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: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
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);
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return retval;
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}
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@ -266,4 +266,8 @@ _K_enter_machcheck:
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.globl ret_from_fork
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ret_from_fork:
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call schedule_tail
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P0 = cmp.eq(R24, #0);
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if P0 jump return_from_syscall
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R0 = R25;
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callr R24
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jump return_from_syscall
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