From: Guo Ren <[email protected]>
This patch converts riscv to use the generic entry infrastructure from
kernel/entry/*. The generic entry makes maintainers' work easier and
codes more elegant. Here are the changes than before:
- More clear entry.S with handle_exception and ret_from_exception
- Get rid of complex custom signal implementation
- More readable syscall procedure
- Little modification on ret_from_fork & ret_from_kernel_thread
- Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
- Use the standard preemption code instead of custom
Signed-off-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Suggested-by: Huacai Chen <[email protected]>
Tested-by: Yipeng Zou <[email protected]>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/csr.h | 1 -
arch/riscv/include/asm/entry-common.h | 8 +
arch/riscv/include/asm/ptrace.h | 10 +-
arch/riscv/include/asm/stacktrace.h | 5 +
arch/riscv/include/asm/syscall.h | 6 +
arch/riscv/include/asm/thread_info.h | 13 +-
arch/riscv/kernel/entry.S | 236 ++++----------------------
arch/riscv/kernel/irq.c | 15 ++
arch/riscv/kernel/ptrace.c | 43 -----
arch/riscv/kernel/signal.c | 21 +--
arch/riscv/kernel/sys_riscv.c | 27 +++
arch/riscv/kernel/traps.c | 70 ++++++--
arch/riscv/mm/fault.c | 16 +-
14 files changed, 173 insertions(+), 299 deletions(-)
create mode 100644 arch/riscv/include/asm/entry-common.h
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7cd981f96f48..6cd3b1d1aeb2 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -57,6 +57,7 @@ config RISCV
select GENERIC_ATOMIC64 if !64BIT
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
select GENERIC_EARLY_IOREMAP
+ select GENERIC_ENTRY
select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
select GENERIC_IDLE_POLL_SETUP
select GENERIC_IOREMAP if MMU
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 0e571f6483d9..7c2b8cdb7b77 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -40,7 +40,6 @@
#define SR_UXL _AC(0x300000000, UL) /* XLEN mask for U-mode */
#define SR_UXL_32 _AC(0x100000000, UL) /* XLEN = 32 for U-mode */
#define SR_UXL_64 _AC(0x200000000, UL) /* XLEN = 64 for U-mode */
-#define SR_UXL_SHIFT 32
#endif
/* SATP flags */
diff --git a/arch/riscv/include/asm/entry-common.h b/arch/riscv/include/asm/entry-common.h
new file mode 100644
index 000000000000..1636ac2af28e
--- /dev/null
+++ b/arch/riscv/include/asm/entry-common.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_ENTRY_COMMON_H
+#define _ASM_RISCV_ENTRY_COMMON_H
+
+#include <asm/stacktrace.h>
+
+#endif /* _ASM_RISCV_ENTRY_COMMON_H */
diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h
index 6ecd461129d2..b5b0adcc85c1 100644
--- a/arch/riscv/include/asm/ptrace.h
+++ b/arch/riscv/include/asm/ptrace.h
@@ -53,6 +53,9 @@ struct pt_regs {
unsigned long orig_a0;
};
+#define PTRACE_SYSEMU 0x1f
+#define PTRACE_SYSEMU_SINGLESTEP 0x20
+
#ifdef CONFIG_64BIT
#define REG_FMT "%016lx"
#else
@@ -121,8 +124,6 @@ extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer);
-int do_syscall_trace_enter(struct pt_regs *regs);
-void do_syscall_trace_exit(struct pt_regs *regs);
/**
* regs_get_register() - get register value from its offset
@@ -172,6 +173,11 @@ static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
return 0;
}
+static inline int regs_irqs_disabled(struct pt_regs *regs)
+{
+ return !(regs->status & SR_PIE);
+}
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_PTRACE_H */
diff --git a/arch/riscv/include/asm/stacktrace.h b/arch/riscv/include/asm/stacktrace.h
index 3450c1912afd..f7e8ef2418b9 100644
--- a/arch/riscv/include/asm/stacktrace.h
+++ b/arch/riscv/include/asm/stacktrace.h
@@ -16,4 +16,9 @@ extern void notrace walk_stackframe(struct task_struct *task, struct pt_regs *re
extern void dump_backtrace(struct pt_regs *regs, struct task_struct *task,
const char *loglvl);
+static inline bool on_thread_stack(void)
+{
+ return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
+}
+
#endif /* _ASM_RISCV_STACKTRACE_H */
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 384a63b86420..6c573f18030b 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -74,5 +74,11 @@ static inline int syscall_get_arch(struct task_struct *task)
#endif
}
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+ return false;
+}
+
asmlinkage long sys_riscv_flush_icache(uintptr_t, uintptr_t, uintptr_t);
+asmlinkage void do_sys_ecall_u(struct pt_regs *regs);
#endif /* _ASM_RISCV_SYSCALL_H */
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 67322f878e0d..7de4fb96f0b5 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -66,6 +66,7 @@ struct thread_info {
long kernel_sp; /* Kernel stack pointer */
long user_sp; /* User stack pointer */
int cpu;
+ unsigned long syscall_work; /* SYSCALL_WORK_ flags */
};
/*
@@ -88,26 +89,18 @@ struct thread_info {
* - pending work-to-be-done flags are in lowest half-word
* - other flags in upper half-word(s)
*/
-#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
#define TIF_SIGPENDING 2 /* signal pending */
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
#define TIF_RESTORE_SIGMASK 4 /* restore signal mask in do_signal() */
#define TIF_MEMDIE 5 /* is terminating due to OOM killer */
-#define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */
-#define TIF_SYSCALL_AUDIT 7 /* syscall auditing */
-#define TIF_SECCOMP 8 /* syscall secure computing */
#define TIF_NOTIFY_SIGNAL 9 /* signal notifications exist */
#define TIF_UPROBE 10 /* uprobe breakpoint or singlestep */
#define TIF_32BIT 11 /* compat-mode 32bit process */
-#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
-#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
-#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
-#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
#define _TIF_UPROBE (1 << TIF_UPROBE)
@@ -115,8 +108,4 @@ struct thread_info {
(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_SIGNAL | _TIF_UPROBE)
-#define _TIF_SYSCALL_WORK \
- (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT | \
- _TIF_SECCOMP)
-
#endif /* _ASM_RISCV_THREAD_INFO_H */
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index b9eda3fcbd6d..9864e784d6a6 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -14,10 +14,6 @@
#include <asm/asm-offsets.h>
#include <asm/errata_list.h>
-#if !IS_ENABLED(CONFIG_PREEMPTION)
-.set resume_kernel, restore_all
-#endif
-
ENTRY(handle_exception)
/*
* If coming from userspace, preserve the user thread pointer and load
@@ -106,19 +102,8 @@ _save_context:
.option norelax
la gp, __global_pointer$
.option pop
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- call __trace_hardirqs_off
-#endif
-
-#ifdef CONFIG_CONTEXT_TRACKING_USER
- /* If previous state is in user mode, call user_exit_callable(). */
- li a0, SR_PP
- and a0, s1, a0
- bnez a0, skip_context_tracking
- call user_exit_callable
-skip_context_tracking:
-#endif
+ move a0, sp /* pt_regs */
+ la ra, ret_from_exception
/*
* MSB of cause differentiates between
@@ -126,134 +111,32 @@ skip_context_tracking:
*/
bge s4, zero, 1f
- la ra, ret_from_exception
-
/* Handle interrupts */
- move a0, sp /* pt_regs */
- la a1, generic_handle_arch_irq
- jr a1
+ tail do_riscv_irq
1:
- /*
- * Exceptions run with interrupts enabled or disabled depending on the
- * state of SR_PIE in m/sstatus.
- */
- andi t0, s1, SR_PIE
- beqz t0, 1f
- /* kprobes, entered via ebreak, must have interrupts disabled. */
- li t0, EXC_BREAKPOINT
- beq s4, t0, 1f
-#ifdef CONFIG_TRACE_IRQFLAGS
- call __trace_hardirqs_on
-#endif
- csrs CSR_STATUS, SR_IE
-
-1:
- la ra, ret_from_exception
- /* Handle syscalls */
- li t0, EXC_SYSCALL
- beq s4, t0, handle_syscall
-
/* Handle other exceptions */
slli t0, s4, RISCV_LGPTR
la t1, excp_vect_table
la t2, excp_vect_table_end
- move a0, sp /* pt_regs */
add t0, t1, t0
/* Check if exception code lies within bounds */
- bgeu t0, t2, 1f
+ bgeu t0, t2, 2f
REG_L t0, 0(t0)
jr t0
-1:
+2:
tail do_trap_unknown
+END(handle_exception)
-handle_syscall:
-#ifdef CONFIG_RISCV_M_MODE
- /*
- * When running is M-Mode (no MMU config), MPIE does not get set.
- * As a result, we need to force enable interrupts here because
- * handle_exception did not do set SR_IE as it always sees SR_PIE
- * being cleared.
- */
- csrs CSR_STATUS, SR_IE
-#endif
-#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING_USER)
- /* Recover a0 - a7 for system calls */
- REG_L a0, PT_A0(sp)
- REG_L a1, PT_A1(sp)
- REG_L a2, PT_A2(sp)
- REG_L a3, PT_A3(sp)
- REG_L a4, PT_A4(sp)
- REG_L a5, PT_A5(sp)
- REG_L a6, PT_A6(sp)
- REG_L a7, PT_A7(sp)
-#endif
- /* save the initial A0 value (needed in signal handlers) */
- REG_S a0, PT_ORIG_A0(sp)
- /*
- * Advance SEPC to avoid executing the original
- * scall instruction on sret
- */
- addi s2, s2, 0x4
- REG_S s2, PT_EPC(sp)
- /* Trace syscalls, but only if requested by the user. */
- REG_L t0, TASK_TI_FLAGS(tp)
- andi t0, t0, _TIF_SYSCALL_WORK
- bnez t0, handle_syscall_trace_enter
-check_syscall_nr:
- /* Check to make sure we don't jump to a bogus syscall number. */
- li t0, __NR_syscalls
- la s0, sys_ni_syscall
- /*
- * Syscall number held in a7.
- * If syscall number is above allowed value, redirect to ni_syscall.
- */
- bgeu a7, t0, 3f
-#ifdef CONFIG_COMPAT
+/*
+ * The ret_from_exception must be called with interrupt disabled. Here is the
+ * caller list:
+ * - handle_exception
+ * - ret_from_fork
+ * - ret_from_kernel_thread
+ */
+ENTRY(ret_from_exception)
REG_L s0, PT_STATUS(sp)
- srli s0, s0, SR_UXL_SHIFT
- andi s0, s0, (SR_UXL >> SR_UXL_SHIFT)
- li t0, (SR_UXL_32 >> SR_UXL_SHIFT)
- sub t0, s0, t0
- bnez t0, 1f
-
- /* Call compat_syscall */
- la s0, compat_sys_call_table
- j 2f
-1:
-#endif
- /* Call syscall */
- la s0, sys_call_table
-2:
- slli t0, a7, RISCV_LGPTR
- add s0, s0, t0
- REG_L s0, 0(s0)
-3:
- jalr s0
-ret_from_syscall:
- /* Set user a0 to kernel a0 */
- REG_S a0, PT_A0(sp)
- /*
- * We didn't execute the actual syscall.
- * Seccomp already set return value for the current task pt_regs.
- * (If it was configured with SECCOMP_RET_ERRNO/TRACE)
- */
-ret_from_syscall_rejected:
-#ifdef CONFIG_DEBUG_RSEQ
- move a0, sp
- call rseq_syscall
-#endif
- /* Trace syscalls, but only if requested by the user. */
- REG_L t0, TASK_TI_FLAGS(tp)
- andi t0, t0, _TIF_SYSCALL_WORK
- bnez t0, handle_syscall_trace_exit
-
-ret_from_exception:
- REG_L s0, PT_STATUS(sp)
- csrc CSR_STATUS, SR_IE
-#ifdef CONFIG_TRACE_IRQFLAGS
- call __trace_hardirqs_off
-#endif
#ifdef CONFIG_RISCV_M_MODE
/* the MPP value is too large to be used as an immediate arg for addi */
li t0, SR_MPP
@@ -261,17 +144,7 @@ ret_from_exception:
#else
andi s0, s0, SR_SPP
#endif
- bnez s0, resume_kernel
-
-resume_userspace:
- /* Interrupts must be disabled here so flags are checked atomically */
- REG_L s0, TASK_TI_FLAGS(tp) /* current_thread_info->flags */
- andi s1, s0, _TIF_WORK_MASK
- bnez s1, work_pending
-
-#ifdef CONFIG_CONTEXT_TRACKING_USER
- call user_enter_callable
-#endif
+ bnez s0, 1f
/* Save unwound kernel stack pointer in thread_info */
addi s0, sp, PT_SIZE_ON_STACK
@@ -282,19 +155,7 @@ resume_userspace:
* structures again.
*/
csrw CSR_SCRATCH, tp
-
-restore_all:
-#ifdef CONFIG_TRACE_IRQFLAGS
- REG_L s1, PT_STATUS(sp)
- andi t0, s1, SR_PIE
- beqz t0, 1f
- call __trace_hardirqs_on
- j 2f
1:
- call __trace_hardirqs_off
-2:
-#endif
- REG_L a0, PT_STATUS(sp)
/*
* The current load reservation is effectively part of the processor's
* state, in the sense that load reservations cannot be shared between
@@ -315,9 +176,11 @@ restore_all:
REG_L a2, PT_EPC(sp)
REG_SC x0, a2, PT_EPC(sp)
- csrw CSR_STATUS, a0
csrw CSR_EPC, a2
+ REG_L a0, PT_STATUS(sp)
+ csrw CSR_STATUS, a0
+
REG_L x1, PT_RA(sp)
REG_L x3, PT_GP(sp)
REG_L x4, PT_TP(sp)
@@ -356,54 +219,10 @@ restore_all:
#else
sret
#endif
-
-#if IS_ENABLED(CONFIG_PREEMPTION)
-resume_kernel:
- REG_L s0, TASK_TI_PREEMPT_COUNT(tp)
- bnez s0, restore_all
- REG_L s0, TASK_TI_FLAGS(tp)
- andi s0, s0, _TIF_NEED_RESCHED
- beqz s0, restore_all
- call preempt_schedule_irq
- j restore_all
-#endif
-
-work_pending:
- /* Enter slow path for supplementary processing */
- la ra, ret_from_exception
- andi s1, s0, _TIF_NEED_RESCHED
- bnez s1, work_resched
-work_notifysig:
- /* Handle pending signals and notify-resume requests */
- csrs CSR_STATUS, SR_IE /* Enable interrupts for do_notify_resume() */
- move a0, sp /* pt_regs */
- move a1, s0 /* current_thread_info->flags */
- tail do_notify_resume
-work_resched:
- tail schedule
-
-/* Slow paths for ptrace. */
-handle_syscall_trace_enter:
- move a0, sp
- call do_syscall_trace_enter
- move t0, a0
- REG_L a0, PT_A0(sp)
- REG_L a1, PT_A1(sp)
- REG_L a2, PT_A2(sp)
- REG_L a3, PT_A3(sp)
- REG_L a4, PT_A4(sp)
- REG_L a5, PT_A5(sp)
- REG_L a6, PT_A6(sp)
- REG_L a7, PT_A7(sp)
- bnez t0, ret_from_syscall_rejected
- j check_syscall_nr
-handle_syscall_trace_exit:
- move a0, sp
- call do_syscall_trace_exit
- j ret_from_exception
+END(ret_from_exception)
#ifdef CONFIG_VMAP_STACK
-handle_kernel_stack_overflow:
+ENTRY(handle_kernel_stack_overflow)
la sp, shadow_stack
addi sp, sp, SHADOW_OVERFLOW_STACK_SIZE
@@ -499,21 +318,24 @@ restore_caller_reg:
REG_S s5, PT_TP(sp)
move a0, sp
tail handle_bad_stack
+END(handle_kernel_stack_overflow)
#endif
-END(handle_exception)
-
ENTRY(ret_from_fork)
+ call schedule_tail
+ move a0, sp /* pt_regs */
la ra, ret_from_exception
- tail schedule_tail
+ tail syscall_exit_to_user_mode
ENDPROC(ret_from_fork)
ENTRY(ret_from_kernel_thread)
call schedule_tail
/* Call fn(arg) */
- la ra, ret_from_exception
move a0, s1
- jr s0
+ jalr s0
+ move a0, sp /* pt_regs */
+ la ra, ret_from_exception
+ tail syscall_exit_to_user_mode
ENDPROC(ret_from_kernel_thread)
@@ -582,7 +404,7 @@ ENTRY(excp_vect_table)
RISCV_PTR do_trap_load_fault
RISCV_PTR do_trap_store_misaligned
RISCV_PTR do_trap_store_fault
- RISCV_PTR do_trap_ecall_u /* system call, gets intercepted */
+ RISCV_PTR do_sys_ecall_u /* system call */
RISCV_PTR do_trap_ecall_s
RISCV_PTR do_trap_unknown
RISCV_PTR do_trap_ecall_m
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 7207fa08d78f..24c2e1bd756a 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -5,6 +5,7 @@
* Copyright (C) 2018 Christoph Hellwig
*/
+#include <linux/entry-common.h>
#include <linux/interrupt.h>
#include <linux/irqchip.h>
#include <linux/seq_file.h>
@@ -22,3 +23,17 @@ void __init init_IRQ(void)
if (!handle_arch_irq)
panic("No interrupt controller found.");
}
+
+asmlinkage void noinstr do_riscv_irq(struct pt_regs *regs)
+{
+ struct pt_regs *old_regs;
+ irqentry_state_t state = irqentry_enter(regs);
+
+ irq_enter_rcu();
+ old_regs = set_irq_regs(regs);
+ handle_arch_irq(regs);
+ set_irq_regs(old_regs);
+ irq_exit_rcu();
+
+ irqentry_exit(regs, state);
+}
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
index 44f4b1ca315d..23c48b14a0e7 100644
--- a/arch/riscv/kernel/ptrace.c
+++ b/arch/riscv/kernel/ptrace.c
@@ -19,9 +19,6 @@
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
-
enum riscv_regset {
REGSET_X,
#ifdef CONFIG_FPU
@@ -228,46 +225,6 @@ long arch_ptrace(struct task_struct *child, long request,
return ret;
}
-/*
- * Allows PTRACE_SYSCALL to work. These are called from entry.S in
- * {handle,ret_from}_syscall.
- */
-__visible int do_syscall_trace_enter(struct pt_regs *regs)
-{
- if (test_thread_flag(TIF_SYSCALL_TRACE))
- if (ptrace_report_syscall_entry(regs))
- return -1;
-
- /*
- * Do the secure computing after ptrace; failures should be fast.
- * If this fails we might have return value in a0 from seccomp
- * (via SECCOMP_RET_ERRNO/TRACE).
- */
- if (secure_computing() == -1)
- return -1;
-
-#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
- if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
- trace_sys_enter(regs, syscall_get_nr(current, regs));
-#endif
-
- audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
- return 0;
-}
-
-__visible void do_syscall_trace_exit(struct pt_regs *regs)
-{
- audit_syscall_exit(regs);
-
- if (test_thread_flag(TIF_SYSCALL_TRACE))
- ptrace_report_syscall_exit(regs, 0);
-
-#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
- if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
- trace_sys_exit(regs, regs_return_value(regs));
-#endif
-}
-
#ifdef CONFIG_COMPAT
static int compat_riscv_gpr_get(struct task_struct *target,
const struct user_regset *regset,
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 5c591123c440..2e365084417e 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -12,6 +12,7 @@
#include <linux/syscalls.h>
#include <linux/resume_user_mode.h>
#include <linux/linkage.h>
+#include <linux/entry-common.h>
#include <asm/ucontext.h>
#include <asm/vdso.h>
@@ -274,7 +275,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
signal_setup_done(ret, ksig, 0);
}
-static void do_signal(struct pt_regs *regs)
+void arch_do_signal_or_restart(struct pt_regs *regs)
{
struct ksignal ksig;
@@ -311,21 +312,3 @@ static void do_signal(struct pt_regs *regs)
*/
restore_saved_sigmask();
}
-
-/*
- * notification of userspace execution resumption
- * - triggered by the _TIF_WORK_MASK flags
- */
-asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
- unsigned long thread_info_flags)
-{
- if (thread_info_flags & _TIF_UPROBE)
- uprobe_notify_resume(regs);
-
- /* Handle pending signal delivery */
- if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
- do_signal(regs);
-
- if (thread_info_flags & _TIF_NOTIFY_RESUME)
- resume_user_mode_work(regs);
-}
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 5d3f2fbeb33c..c86d0eafdf6a 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -5,8 +5,10 @@
* Copyright (C) 2017 SiFive
*/
+#include <linux/entry-common.h>
#include <linux/syscalls.h>
#include <asm/unistd.h>
+#include <asm/syscall.h>
#include <asm/cacheflush.h>
#include <asm-generic/mman-common.h>
@@ -69,3 +71,28 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
return 0;
}
+
+typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong);
+
+asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
+{
+ syscall_t syscall;
+ ulong nr = regs->a7;
+
+ regs->epc += 4;
+ regs->orig_a0 = regs->a0;
+ regs->a0 = -ENOSYS;
+
+ nr = syscall_enter_from_user_mode(regs, nr);
+#ifdef CONFIG_COMPAT
+ if ((regs->status & SR_UXL) == SR_UXL_32)
+ syscall = compat_sys_call_table[nr];
+ else
+#endif
+ syscall = sys_call_table[nr];
+
+ if (nr < NR_syscalls)
+ regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
+ regs->a3, regs->a4, regs->a5, regs->a6);
+ syscall_exit_to_user_mode(regs);
+}
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index f7fa973558bc..ee9a0ef672e9 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/irq.h>
#include <linux/kexec.h>
+#include <linux/entry-common.h>
#include <asm/asm-prototypes.h>
#include <asm/bug.h>
@@ -99,10 +100,19 @@ static void do_trap_error(struct pt_regs *regs, int signo, int code,
#else
#define __trap_section noinstr
#endif
-#define DO_ERROR_INFO(name, signo, code, str) \
-asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
-{ \
- do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
+#define DO_ERROR_INFO(name, signo, code, str) \
+asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
+{ \
+ if (user_mode(regs)) { \
+ irqentry_enter_from_user_mode(regs); \
+ do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
+ irqentry_exit_to_user_mode(regs); \
+ } else { \
+ irqentry_state_t irq_state = irqentry_nmi_enter(regs); \
+ do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
+ irqentry_nmi_exit(regs, irq_state); \
+ } \
+ BUG_ON(!irqs_disabled()); \
}
DO_ERROR_INFO(do_trap_unknown,
@@ -126,18 +136,38 @@ int handle_misaligned_store(struct pt_regs *regs);
asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs)
{
- if (!handle_misaligned_load(regs))
- return;
- do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
- "Oops - load address misaligned");
+ if (user_mode(regs)) {
+ irqentry_enter_from_user_mode(regs);
+ if (handle_misaligned_load(regs))
+ do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
+ "Oops - load address misaligned");
+ irqentry_exit_to_user_mode(regs);
+ } else {
+ irqentry_state_t irq_state = irqentry_nmi_enter(regs);
+ if (handle_misaligned_load(regs))
+ do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
+ "Oops - load address misaligned");
+ irqentry_nmi_exit(regs, irq_state);
+ }
+ BUG_ON(!irqs_disabled());
}
asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs)
{
- if (!handle_misaligned_store(regs))
- return;
- do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
- "Oops - store (or AMO) address misaligned");
+ if (user_mode(regs)) {
+ irqentry_enter_from_user_mode(regs);
+ if (handle_misaligned_store(regs))
+ do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
+ "Oops - store (or AMO) address misaligned");
+ irqentry_exit_to_user_mode(regs);
+ } else {
+ irqentry_state_t irq_state = irqentry_nmi_enter(regs);
+ if (handle_misaligned_store(regs))
+ do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
+ "Oops - store (or AMO) address misaligned");
+ irqentry_nmi_exit(regs, irq_state);
+ }
+ BUG_ON(!irqs_disabled());
}
#endif
DO_ERROR_INFO(do_trap_store_fault,
@@ -159,7 +189,7 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
return GET_INSN_LENGTH(insn);
}
-asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
+static void __do_trap_break(struct pt_regs *regs)
{
#ifdef CONFIG_KPROBES
if (kprobe_single_step_handler(regs))
@@ -189,6 +219,20 @@ asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
else
die(regs, "Kernel BUG");
}
+
+asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs)
+{
+ if (user_mode(regs)) {
+ irqentry_enter_from_user_mode(regs);
+ __do_trap_break(regs);
+ irqentry_exit_to_user_mode(regs);
+ } else {
+ irqentry_state_t irq_state = irqentry_nmi_enter(regs);
+ __do_trap_break(regs);
+ irqentry_nmi_exit(regs, irq_state);
+ }
+ BUG_ON(!irqs_disabled());
+}
NOKPROBE_SYMBOL(do_trap_break);
#ifdef CONFIG_GENERIC_BUG
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index b26f68eac61c..5cbea6c55a59 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -15,6 +15,7 @@
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#include <linux/kfence.h>
+#include <linux/entry-common.h>
#include <asm/ptrace.h>
#include <asm/tlbflush.h>
@@ -204,7 +205,7 @@ static inline bool access_error(unsigned long cause, struct vm_area_struct *vma)
* This routine handles page faults. It determines the address and the
* problem, and then passes it off to one of the appropriate routines.
*/
-asmlinkage void noinstr do_page_fault(struct pt_regs *regs)
+static void __do_page_fault(struct pt_regs *regs)
{
struct task_struct *tsk;
struct vm_area_struct *vma;
@@ -251,7 +252,7 @@ asmlinkage void noinstr do_page_fault(struct pt_regs *regs)
}
#endif
/* Enable interrupts if they were enabled in the parent context. */
- if (likely(regs->status & SR_PIE))
+ if (!regs_irqs_disabled(regs))
local_irq_enable();
/*
@@ -351,4 +352,15 @@ asmlinkage void noinstr do_page_fault(struct pt_regs *regs)
}
return;
}
+
+asmlinkage void noinstr do_page_fault(struct pt_regs *regs)
+{
+ irqentry_state_t state = irqentry_enter(regs);
+
+ __do_page_fault(regs);
+
+ local_irq_disable();
+
+ irqentry_exit(regs, state);
+}
NOKPROBE_SYMBOL(do_page_fault);
--
2.36.1
On Thu, 2022-11-03 at 03:50 -0400, [email protected] wrote:
[...]
> --- a/arch/riscv/kernel/sys_riscv.c
> +++ b/arch/riscv/kernel/sys_riscv.c
[...]
> +asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
> +{
> + syscall_t syscall;
> + ulong nr = regs->a7;
> +
> + regs->epc += 4;
> + regs->orig_a0 = regs->a0;
> + regs->a0 = -ENOSYS;
> +
> + nr = syscall_enter_from_user_mode(regs, nr);
> +#ifdef CONFIG_COMPAT
> + if ((regs->status & SR_UXL) == SR_UXL_32)
> + syscall = compat_sys_call_table[nr];
> + else
> +#endif
> + syscall = sys_call_table[nr];
> +
> + if (nr < NR_syscalls)
This bounds check needs to be done before indexing the system call
table, not after.
Ben.
> + regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
> + regs->a3, regs->a4, regs->a5, regs->a6);
> + syscall_exit_to_user_mode(regs);
> +}
[...]
--
Ben Hutchings
This sentence contradicts itself - no actually it doesn't.
On Mon, Nov 28, 2022 at 12:26 AM Ben Hutchings <[email protected]> wrote:
>
> On Thu, 2022-11-03 at 03:50 -0400, [email protected] wrote:
> [...]
> > --- a/arch/riscv/kernel/sys_riscv.c
> > +++ b/arch/riscv/kernel/sys_riscv.c
> [...]
> > +asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
> > +{
> > + syscall_t syscall;
> > + ulong nr = regs->a7;
> > +
> > + regs->epc += 4;
> > + regs->orig_a0 = regs->a0;
> > + regs->a0 = -ENOSYS;
> > +
> > + nr = syscall_enter_from_user_mode(regs, nr);
> > +#ifdef CONFIG_COMPAT
> > + if ((regs->status & SR_UXL) == SR_UXL_32)
> > + syscall = compat_sys_call_table[nr];
> > + else
> > +#endif
> > + syscall = sys_call_table[nr];
> > +
> > + if (nr < NR_syscalls)
>
> This bounds check needs to be done before indexing the system call
> table, not after.
Yes, you are right. That would cause a wrong pointer bug. Here is the
new version:
asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
{
syscall_t syscall;
ulong nr = regs->a7;
regs->epc += 4;
regs->orig_a0 = regs->a0;
regs->a0 = -ENOSYS;
nr = syscall_enter_from_user_mode(regs, nr);
if (nr < NR_syscalls) {
#ifdef CONFIG_COMPAT
if ((regs->status & SR_UXL) == SR_UXL_32)
syscall = compat_sys_call_table[nr];
else
#endif
syscall = sys_call_table[nr];
regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
regs->a3, regs->a4, regs->a5, regs->a6);
}
syscall_exit_to_user_mode(regs);
}
>
> Ben.
>
> > + regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
> > + regs->a3, regs->a4, regs->a5, regs->a6);
> > + syscall_exit_to_user_mode(regs);
> > +}
> [...]
>
> --
> Ben Hutchings
> This sentence contradicts itself - no actually it doesn't.
--
Best Regards
Guo Ren
[email protected] writes:
> From: Guo Ren <[email protected]>
>
> This patch converts riscv to use the generic entry infrastructure from
> kernel/entry/*. The generic entry makes maintainers' work easier and
> codes more elegant. Here are the changes than before:
>
> - More clear entry.S with handle_exception and ret_from_exception
> - Get rid of complex custom signal implementation
> - More readable syscall procedure
> - Little modification on ret_from_fork & ret_from_kernel_thread
> - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
> - Use the standard preemption code instead of custom
>
> Signed-off-by: Guo Ren <[email protected]>
> Signed-off-by: Guo Ren <[email protected]>
> Suggested-by: Huacai Chen <[email protected]>
> Tested-by: Yipeng Zou <[email protected]>
> ---
[...]
> diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
> index 5d3f2fbeb33c..c86d0eafdf6a 100644
> --- a/arch/riscv/kernel/sys_riscv.c
> +++ b/arch/riscv/kernel/sys_riscv.c
> @@ -5,8 +5,10 @@
> * Copyright (C) 2017 SiFive
> */
>
> +#include <linux/entry-common.h>
> #include <linux/syscalls.h>
> #include <asm/unistd.h>
> +#include <asm/syscall.h>
> #include <asm/cacheflush.h>
> #include <asm-generic/mman-common.h>
>
> @@ -69,3 +71,28 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
>
> return 0;
> }
> +
> +typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong);
> +
> +asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
> +{
> + syscall_t syscall;
> + ulong nr = regs->a7;
> +
> + regs->epc += 4;
> + regs->orig_a0 = regs->a0;
> + regs->a0 = -ENOSYS;
> +
> + nr = syscall_enter_from_user_mode(regs, nr);
> +#ifdef CONFIG_COMPAT
> + if ((regs->status & SR_UXL) == SR_UXL_32)
> + syscall = compat_sys_call_table[nr];
> + else
> +#endif
> + syscall = sys_call_table[nr];
> +
> + if (nr < NR_syscalls)
> + regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
> + regs->a3, regs->a4, regs->a5,
> regs->a6);
Now that we're doing the "pt_regs to call" dance, it would make sense to
introduce a syscall wrapper (like x86 and arm64) for riscv, so that we
don't need to unwrap all regs for all syscalls (See __MAP() in
include/linux/syscalls.h). That would be an optimization, so it could be
done as a follow-up, and not part of the series.
Björn
On Mon, Dec 5, 2022 at 6:49 PM Björn Töpel <[email protected]> wrote:
>
> [email protected] writes:
>
> > From: Guo Ren <[email protected]>
> >
> > This patch converts riscv to use the generic entry infrastructure from
> > kernel/entry/*. The generic entry makes maintainers' work easier and
> > codes more elegant. Here are the changes than before:
> >
> > - More clear entry.S with handle_exception and ret_from_exception
> > - Get rid of complex custom signal implementation
> > - More readable syscall procedure
> > - Little modification on ret_from_fork & ret_from_kernel_thread
> > - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
> > - Use the standard preemption code instead of custom
> >
> > Signed-off-by: Guo Ren <[email protected]>
> > Signed-off-by: Guo Ren <[email protected]>
> > Suggested-by: Huacai Chen <[email protected]>
> > Tested-by: Yipeng Zou <[email protected]>
> > ---
>
> [...]
>
> > diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
> > index 5d3f2fbeb33c..c86d0eafdf6a 100644
> > --- a/arch/riscv/kernel/sys_riscv.c
> > +++ b/arch/riscv/kernel/sys_riscv.c
> > @@ -5,8 +5,10 @@
> > * Copyright (C) 2017 SiFive
> > */
> >
> > +#include <linux/entry-common.h>
> > #include <linux/syscalls.h>
> > #include <asm/unistd.h>
> > +#include <asm/syscall.h>
> > #include <asm/cacheflush.h>
> > #include <asm-generic/mman-common.h>
> >
> > @@ -69,3 +71,28 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
> >
> > return 0;
> > }
> > +
> > +typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong);
> > +
> > +asmlinkage void do_sys_ecall_u(struct pt_regs *regs)
> > +{
> > + syscall_t syscall;
> > + ulong nr = regs->a7;
> > +
> > + regs->epc += 4;
> > + regs->orig_a0 = regs->a0;
> > + regs->a0 = -ENOSYS;
> > +
> > + nr = syscall_enter_from_user_mode(regs, nr);
> > +#ifdef CONFIG_COMPAT
> > + if ((regs->status & SR_UXL) == SR_UXL_32)
> > + syscall = compat_sys_call_table[nr];
> > + else
> > +#endif
> > + syscall = sys_call_table[nr];
> > +
> > + if (nr < NR_syscalls)
> > + regs->a0 = syscall(regs->orig_a0, regs->a1, regs->a2,
> > + regs->a3, regs->a4, regs->a5,
> > regs->a6);
>
> Now that we're doing the "pt_regs to call" dance, it would make sense to
> introduce a syscall wrapper (like x86 and arm64) for riscv, so that we
> don't need to unwrap all regs for all syscalls (See __MAP() in
> include/linux/syscalls.h). That would be an optimization, so it could be
> done as a follow-up, and not part of the series.
Thx for the reminder; I will have a look at "pt_regs to call."
>
>
> Björn
--
Best Regards
Guo Ren