linux-stable/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 11:07:12 +00:00
#include <linux/cache.h>
#include <linux/prctl.h>
#include <vdso/processor.h>
#include <asm/ptrace.h>
/*
* addr is a hint to the maximum userspace address that mmap should provide, so
* this macro needs to return the largest address space available so that
* mmap_end < addr, being mmap_end the top of that address space.
* See Documentation/arch/riscv/vm-layout.rst for more details.
*/
#define arch_get_mmap_end(addr, len, flags) \
({ \
unsigned long mmap_end; \
typeof(addr) _addr = (addr); \
if ((_addr) == 0 || is_compat_task() || \
((_addr + len) > BIT(VA_BITS - 1))) \
mmap_end = STACK_TOP_MAX; \
else \
mmap_end = (_addr + len); \
mmap_end; \
})
#define arch_get_mmap_base(addr, base) \
({ \
unsigned long mmap_base; \
typeof(addr) _addr = (addr); \
typeof(base) _base = (base); \
unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base); \
if ((_addr) == 0 || is_compat_task() || \
((_addr + len) > BIT(VA_BITS - 1))) \
mmap_base = (_base); \
else \
mmap_base = (_addr + len) - rnd_gap; \
mmap_base; \
})
#ifdef CONFIG_64BIT
#define DEFAULT_MAP_WINDOW (UL(1) << (MMAP_VA_BITS - 1))
#define STACK_TOP_MAX TASK_SIZE_64
#else
#define DEFAULT_MAP_WINDOW TASK_SIZE
#define STACK_TOP_MAX TASK_SIZE
#endif
#define STACK_ALIGN 16
#define STACK_TOP DEFAULT_MAP_WINDOW
/*
* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#ifdef CONFIG_64BIT
#define TASK_UNMAPPED_BASE PAGE_ALIGN((UL(1) << MMAP_MIN_VA_BITS) / 3)
#else
#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3)
#endif
#ifndef __ASSEMBLY__
struct task_struct;
struct pt_regs;
/*
* We use a flag to track in-kernel Vector context. Currently the flag has the
* following meaning:
*
* - bit 0: indicates whether the in-kernel Vector context is active. The
* activation of this state disables the preemption. On a non-RT kernel, it
* also disable bh.
* - bits 8: is used for tracking preemptible kernel-mode Vector, when
* RISCV_ISA_V_PREEMPTIVE is enabled. Calling kernel_vector_begin() does not
* disable the preemption if the thread's kernel_vstate.datap is allocated.
* Instead, the kernel set this bit field. Then the trap entry/exit code
* knows if we are entering/exiting the context that owns preempt_v.
* - 0: the task is not using preempt_v
* - 1: the task is actively using preempt_v. But whether does the task own
* the preempt_v context is decided by bits in RISCV_V_CTX_DEPTH_MASK.
* - bit 16-23 are RISCV_V_CTX_DEPTH_MASK, used by context tracking routine
* when preempt_v starts:
* - 0: the task is actively using, and own preempt_v context.
* - non-zero: the task was using preempt_v, but then took a trap within.
* Thus, the task does not own preempt_v. Any use of Vector will have to
* save preempt_v, if dirty, and fallback to non-preemptible kernel-mode
* Vector.
* - bit 30: The in-kernel preempt_v context is saved, and requries to be
* restored when returning to the context that owns the preempt_v.
* - bit 31: The in-kernel preempt_v context is dirty, as signaled by the
* trap entry code. Any context switches out-of current task need to save
* it to the task's in-kernel V context. Also, any traps nesting on-top-of
* preempt_v requesting to use V needs a save.
*/
#define RISCV_V_CTX_DEPTH_MASK 0x00ff0000
#define RISCV_V_CTX_UNIT_DEPTH 0x00010000
#define RISCV_KERNEL_MODE_V 0x00000001
#define RISCV_PREEMPT_V 0x00000100
#define RISCV_PREEMPT_V_DIRTY 0x80000000
#define RISCV_PREEMPT_V_NEED_RESTORE 0x40000000
/* 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;
u32 riscv_v_flags;
u32 vstate_ctrl;
struct __riscv_v_ext_state vstate;
unsigned long align_ctl;
struct __riscv_v_ext_state kernel_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, \
.align_ctl = PR_UNALIGN_NOPRINT, \
}
#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");
}
extern phys_addr_t dma32_phys_limit;
struct device_node;
int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);
int riscv_early_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 11:07:12 +00:00
extern unsigned long signal_minsigstksz __ro_after_init;
#ifdef CONFIG_RISCV_ISA_V
/* Userspace interface for PR_RISCV_V_{SET,GET}_VS prctl()s: */
#define RISCV_V_SET_CONTROL(arg) riscv_v_vstate_ctrl_set_current(arg)
#define RISCV_V_GET_CONTROL() riscv_v_vstate_ctrl_get_current()
extern long riscv_v_vstate_ctrl_set_current(unsigned long arg);
extern long riscv_v_vstate_ctrl_get_current(void);
#endif /* CONFIG_RISCV_ISA_V */
extern int get_unalign_ctl(struct task_struct *tsk, unsigned long addr);
extern int set_unalign_ctl(struct task_struct *tsk, unsigned int val);
#define GET_UNALIGN_CTL(tsk, addr) get_unalign_ctl((tsk), (addr))
#define SET_UNALIGN_CTL(tsk, val) set_unalign_ctl((tsk), (val))
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_PROCESSOR_H */