linux/arch/riscv/include/asm/processor.h

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 Regents of the University of California
*/
#ifndef _ASM_RISCV_PROCESSOR_H
#define _ASM_RISCV_PROCESSOR_H
#include <linux/const.h>
riscv: signal: Report signal frame size to userspace via auxv The vector register belongs to the signal context. They need to be stored and restored as entering and leaving the signal handler. According to the V-extension specification, the maximum length of the vector registers can be 2^16. Hence, if userspace refers to the MINSIGSTKSZ to create a sigframe, it may not be enough. To resolve this problem, this patch refers to the commit 94b07c1f8c39c ("arm64: signal: Report signal frame size to userspace via auxv") to enable userspace to know the minimum required sigframe size through the auxiliary vector and use it to allocate enough memory for signal context. Note that auxv always reports size of the sigframe as if V exists for all starting processes, whenever the kernel has CONFIG_RISCV_ISA_V. The reason is that users usually reference this value to allocate an alternative signal stack, and the user may use V anytime. So the user must reserve a space for V-context in sigframe in case that the signal handler invokes after the kernel allocating V. Signed-off-by: Greentime Hu <greentime.hu@sifive.com> Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Andy Chiu <andy.chiu@sifive.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230605110724.21391-16-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-05 14:07:12 +03:00
#include <linux/cache.h>
#include <vdso/processor.h>
#include <asm/ptrace.h>
/*
* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3)
#define STACK_TOP TASK_SIZE
#ifdef CONFIG_64BIT
#define STACK_TOP_MAX TASK_SIZE_64
#else
#define STACK_TOP_MAX TASK_SIZE
#endif
#define STACK_ALIGN 16
#ifndef __ASSEMBLY__
struct task_struct;
struct pt_regs;
/* CPU-specific state of a task */
struct thread_struct {
/* Callee-saved registers */
unsigned long ra;
unsigned long sp; /* Kernel mode stack */
unsigned long s[12]; /* s[0]: frame pointer */
struct __riscv_d_ext_state fstate;
unsigned long bad_cause;
struct __riscv_v_ext_state vstate;
};
/* Whitelist the fstate from the task_struct for hardened usercopy */
static inline void arch_thread_struct_whitelist(unsigned long *offset,
unsigned long *size)
{
*offset = offsetof(struct thread_struct, fstate);
*size = sizeof_field(struct thread_struct, fstate);
}
#define INIT_THREAD { \
.sp = sizeof(init_stack) + (long)&init_stack, \
}
#define task_pt_regs(tsk) \
((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE \
- ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->epc)
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp)
/* Do necessary setup to start up a newly executed thread. */
extern void start_thread(struct pt_regs *regs,
unsigned long pc, unsigned long sp);
extern unsigned long __get_wchan(struct task_struct *p);
static inline void wait_for_interrupt(void)
{
__asm__ __volatile__ ("wfi");
}
struct device_node;
int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);
int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid);
extern void riscv_fill_hwcap(void);
extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
riscv: signal: Report signal frame size to userspace via auxv The vector register belongs to the signal context. They need to be stored and restored as entering and leaving the signal handler. According to the V-extension specification, the maximum length of the vector registers can be 2^16. Hence, if userspace refers to the MINSIGSTKSZ to create a sigframe, it may not be enough. To resolve this problem, this patch refers to the commit 94b07c1f8c39c ("arm64: signal: Report signal frame size to userspace via auxv") to enable userspace to know the minimum required sigframe size through the auxiliary vector and use it to allocate enough memory for signal context. Note that auxv always reports size of the sigframe as if V exists for all starting processes, whenever the kernel has CONFIG_RISCV_ISA_V. The reason is that users usually reference this value to allocate an alternative signal stack, and the user may use V anytime. So the user must reserve a space for V-context in sigframe in case that the signal handler invokes after the kernel allocating V. Signed-off-by: Greentime Hu <greentime.hu@sifive.com> Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Andy Chiu <andy.chiu@sifive.com> Acked-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Link: https://lore.kernel.org/r/20230605110724.21391-16-andy.chiu@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-05 14:07:12 +03:00
extern unsigned long signal_minsigstksz __ro_after_init;
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_PROCESSOR_H */