Commit f955aa87 authored by Charlie Jenkins's avatar Charlie Jenkins Committed by Thomas Gleixner
Browse files

riscv: entry: Convert ret_from_fork() to C 



Move the main section of ret_from_fork() to C to allow inlining of
syscall_exit_to_user_mode().

Signed-off-by: default avatarCharlie Jenkins <charlie@rivosinc.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/all/20250320-riscv_optimize_entry-v6-1-63e187e26041@rivosinc.com
parent b4432656

arch/riscv/include/asm/asm-prototypes.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ DECLARE_DO_ERROR_INFO(do_trap_ecall_s); 
DECLARE_DO_ERROR_INFO(do_trap_ecall_m);

DECLARE_DO_ERROR_INFO(do_trap_break);



asmlinkage void ret_from_fork(void *fn_arg, int (*fn)(void *), struct pt_regs *regs);

asmlinkage void handle_bad_stack(struct pt_regs *regs);

asmlinkage void do_page_fault(struct pt_regs *regs);

asmlinkage void do_irq(struct pt_regs *regs);

arch/riscv/kernel/entry.S

+6 −9
Original line number Diff line number Diff line
@@ -319,17 +319,14 @@ SYM_CODE_END(handle_kernel_stack_overflow) 
ASM_NOKPROBE(handle_kernel_stack_overflow)

#endif



SYM_CODE_START(ret_from_fork)

SYM_CODE_START(ret_from_fork_asm)

	call schedule_tail

	beqz s0, 1f	/* not from kernel thread */

	/* Call fn(arg) */

	move a0, s1

	jalr s0

1:

	move a0, sp /* pt_regs */

	call syscall_exit_to_user_mode

	move a0, s1 /* fn_arg */

	move a1, s0 /* fn */

	move a2, sp /* pt_regs */

	call ret_from_fork

	j ret_from_exception

SYM_CODE_END(ret_from_fork)

SYM_CODE_END(ret_from_fork_asm)



#ifdef CONFIG_IRQ_STACKS

/*

arch/riscv/kernel/process.c

+12 −2
Original line number Diff line number Diff line
@@ -17,7 +17,9 @@ 
#include <linux/ptrace.h>

#include <linux/uaccess.h>

#include <linux/personality.h>

#include <linux/entry-common.h>



#include <asm/asm-prototypes.h>

#include <asm/unistd.h>

#include <asm/processor.h>

#include <asm/csr.h>
@@ -36,7 +38,7 @@ unsigned long __stack_chk_guard __read_mostly; 
EXPORT_SYMBOL(__stack_chk_guard);

#endif



extern asmlinkage void ret_from_fork(void);

extern asmlinkage void ret_from_fork_asm(void);



void noinstr arch_cpu_idle(void)

{
@@ -206,6 +208,14 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 
	return 0;

}



asmlinkage void ret_from_fork(void *fn_arg, int (*fn)(void *), struct pt_regs *regs)

{

	if (unlikely(fn))

		fn(fn_arg);



	syscall_exit_to_user_mode(regs);

}



int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)

{

	unsigned long clone_flags = args->flags;
@@ -242,7 +252,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 
	p->thread.riscv_v_flags = 0;

	if (has_vector() || has_xtheadvector())

		riscv_v_thread_alloc(p);

	p->thread.ra = (unsigned long)ret_from_fork;

	p->thread.ra = (unsigned long)ret_from_fork_asm;

	p->thread.sp = (unsigned long)childregs; /* kernel sp */

	return 0;

}