Re: [PATCH -next V16 4/7] riscv: entry: Convert to generic entry

Guo Ren
2023-02-05T13:56:23Z

On Sun, Feb 5, 2023 at 6:43 PM Conor Dooley <conor@kernel.org> wrote:
>
> Hey Guo Ren,
>
> On 4 February 2023 08:02:10 GMT+01:00, guoren@kernel.org wrote:
> >From: Guo Ren <guoren@linux.alibaba.com>
> >
> >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:
> >
> > - More clear entry.S with handle_exception and ret_from_exception
> > - Get rid of complex custom signal implementation
> > - Move syscall procedure from assembly to C, which is much more
> > readable.
> > - Connect ret_from_fork & ret_from_kernel_thread to generic entry.
> > - Wrap with irqentry_enter/exit and syscall_enter/exit_from_user_mode
> > - Use the standard preemption code instead of custom
> >
> >Suggested-by: Huacai Chen <chenhuacai@kernel.org>
> >Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
> >Tested-by: Yipeng Zou <zouyipeng@huawei.com>
> >Tested-by: Jisheng Zhang <jszhang@kernel.org>
> >Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> >Signed-off-by: Guo Ren <guoren@kernel.org>
> >Cc: Ben Hutchings <ben@decadent.org.uk>
> >---
>
> Got some new errors added by this patch:
> https://gist.github.com/conor-pwbot/3b300050a7a4a197bca809935584d809
>
> Unfortunately I'm away from a computer at FOSDEM, so I haven't done any investigation
> of the warnings.
> Should be reproduceable with gcc-12 allmodconfig.
Thx for report, but:
The spin_shadow_stack is from '7e1864332fbc ("riscv: fix race when
vmap stack overflow")'. Not this patch.

New errors added:
--- /tmp/tmp.nyMxgc6CGx 2023-02-05 05:12:59.949595120 +0000
+++ /tmp/tmp.5td5fIdaHX 2023-02-05 05:12:59.961595119 +0000
@@ -10 +10 @@
- 1 ../arch/riscv/kernel/traps.c:231:15: warning: symbol
'spin_shadow_stack' was not declared. Should it be static?
+ 1 ../arch/riscv/kernel/traps.c:335:15: warning: symbol
'spin_shadow_stack' was not declared. Should it be static?
@@ -9109 +9109 @@
- 37 ../include/linux/fortify-string.h:522:25: warning: call to
'__read_overflow2_field' declared with attribute warning: detected
read beyond size of field (2nd parameter); maybe use struct_group()?
[-Wattribute-warning]
+ 38 ../include/linux/fortify-string.h:522:25: warning: call to
'__read_overflow2_field' declared with attribute warning: detected
read beyond size of field (2nd parameter); maybe use struct_group()?
[-Wattribute-warning]
Per-file breakdown
--- /tmp/tmp.bHiHUVMzmZ 2023-02-05 05:13:00.109595117 +0000
+++ /tmp/tmp.kUkOd6TrGj 2023-02-05 05:13:00.257595114 +0000
@@ -1197 +1197 @@
- 65 ../include/linux/fortify-string.h
+ 66 ../include/linux/fortify-string.h

Seems the line number change would cause your script to report old
errors as new. So it would be best to improve the check script, such
as ignoring the first column line number :)

>
> Thanks,
> Conor.
>
>
> > arch/riscv/Kconfig | 1 +
> > arch/riscv/include/asm/asm-prototypes.h | 2 +
> > arch/riscv/include/asm/csr.h | 1 -
> > arch/riscv/include/asm/entry-common.h | 11 ++
> > arch/riscv/include/asm/ptrace.h | 10 +-
> > arch/riscv/include/asm/stacktrace.h | 5 +
> > arch/riscv/include/asm/syscall.h | 21 ++
> > arch/riscv/include/asm/thread_info.h | 13 +-
> > arch/riscv/kernel/entry.S | 242 ++++--------------------
> > arch/riscv/kernel/head.h | 1 -
> > arch/riscv/kernel/ptrace.c | 43 -----
> > arch/riscv/kernel/signal.c | 29 +--
> > arch/riscv/kernel/traps.c | 140 ++++++++++++--
> > arch/riscv/mm/fault.c | 6 +-
> > 14 files changed, 210 insertions(+), 315 deletions(-)
> > create mode 100644 arch/riscv/include/asm/entry-common.h
> >
> >diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> >index 7c814fbf9527..cbac7b4e3e06 100644
> >--- a/arch/riscv/Kconfig
> >+++ b/arch/riscv/Kconfig
> >@@ -58,6 +58,7 @@ 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/asm-prototypes.h b/arch/riscv/include/asm/asm-prototypes.h
> >index ef386fcf3939..61ba8ed43d8f 100644
> >--- a/arch/riscv/include/asm/asm-prototypes.h
> >+++ b/arch/riscv/include/asm/asm-prototypes.h
> >@@ -27,5 +27,7 @@ DECLARE_DO_ERROR_INFO(do_trap_break);
> >
> > asmlinkage unsigned long get_overflow_stack(void);
> > 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);
> >
> > #endif /* _ASM_RISCV_PROTOTYPES_H */
> >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..6e4dee49d84b
> >--- /dev/null
> >+++ b/arch/riscv/include/asm/entry-common.h
> >@@ -0,0 +1,11 @@
> >+/* SPDX-License-Identifier: GPL-2.0 */
> >+
> >+#ifndef _ASM_RISCV_ENTRY_COMMON_H
> >+#define _ASM_RISCV_ENTRY_COMMON_H
> >+
> >+#include <asm/stacktrace.h>
> >+
> >+void handle_page_fault(struct pt_regs *regs);
> >+void handle_break(struct pt_regs *regs);
> >+
> >+#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..736110e1fd78 100644
> >--- a/arch/riscv/include/asm/syscall.h
> >+++ b/arch/riscv/include/asm/syscall.h
> >@@ -74,5 +74,26 @@ static inline int syscall_get_arch(struct task_struct *task)
> > #endif
> > }
> >
> >+typedef long (*syscall_t)(ulong, ulong, ulong, ulong, ulong, ulong, ulong);
> >+static inline void syscall_handler(struct pt_regs *regs, ulong syscall)
> >+{
> >+ syscall_t fn;
> >+
> >+#ifdef CONFIG_COMPAT
> >+ if ((regs->status & SR_UXL) == SR_UXL_32)
> >+ fn = compat_sys_call_table[syscall];
> >+ else
> >+#endif
> >+ fn = sys_call_table[syscall];
> >+
> >+ regs->a0 = fn(regs->orig_a0, regs->a1, regs->a2,
> >+ regs->a3, regs->a4, regs->a5, regs->a6);
> >+}
> >+
> >+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);
> > #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 99d38fdf8b18..bc322f92ba34 100644
> >--- a/arch/riscv/kernel/entry.S
> >+++ b/arch/riscv/kernel/entry.S
> >@@ -14,11 +14,7 @@
> > #include <asm/asm-offsets.h>
> > #include <asm/errata_list.h>
> >
> >-#if !IS_ENABLED(CONFIG_PREEMPTION)
> >-.set resume_kernel, restore_all
> >-#endif
> >-
> >-ENTRY(handle_exception)
> >+SYM_CODE_START(handle_exception)
> > /*
> > * If coming from userspace, preserve the user thread pointer and load
> > * the kernel thread pointer. If we came from the kernel, the scratch
> >@@ -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
> >@@ -126,38 +111,13 @@ 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
> >-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
> >-
> >+ tail do_irq
> > 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
> >@@ -165,95 +125,17 @@ skip_context_tracking:
> > jr t0
> > 1:
> > tail do_trap_unknown
> >+SYM_CODE_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
> >- 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
> >-
> >+/*
> >+ * The ret_from_exception must be called with interrupt disabled. Here is the
> >+ * caller list:
> >+ * - handle_exception
> >+ * - ret_from_fork
> >+ * - ret_from_kernel_thread
> >+ */
> > SYM_CODE_START_NOALIGN(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 +143,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception)
> > #else
> > andi s0, s0, SR_SPP
> > #endif
> >- bnez s0, resume_kernel
> >-SYM_CODE_END(ret_from_exception)
> >-
> >- /* 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, resume_userspace_slow
> >-resume_userspace:
> >-#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
> >@@ -282,18 +154,7 @@ 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
> >@@ -356,47 +217,10 @@ 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
> >-
> >-resume_userspace_slow:
> >- /* Enter slow path for supplementary processing */
> >- move a0, sp /* pt_regs */
> >- move a1, s0 /* current_thread_info->flags */
> >- call do_work_pending
> >- j resume_userspace
> >-
> >-/* 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
> >+SYM_CODE_END(ret_from_exception)
> >
> > #ifdef CONFIG_VMAP_STACK
> >-handle_kernel_stack_overflow:
> >+SYM_CODE_START_LOCAL(handle_kernel_stack_overflow)
> > /*
> > * Takes the psuedo-spinlock for the shadow stack, in case multiple
> > * harts are concurrently overflowing their kernel stacks. We could
> >@@ -505,23 +329,25 @@ restore_caller_reg:
> > REG_S s5, PT_TP(sp)
> > move a0, sp
> > tail handle_bad_stack
> >+SYM_CODE_END(handle_kernel_stack_overflow)
> > #endif
> >
> >-END(handle_exception)
> >-
> >-ENTRY(ret_from_fork)
> >+SYM_CODE_START(ret_from_fork)
> >+ call schedule_tail
> >+ move a0, sp /* pt_regs */
> > la ra, ret_from_exception
> >- tail schedule_tail
> >-ENDPROC(ret_from_fork)
> >+ tail syscall_exit_to_user_mode
> >+SYM_CODE_END(ret_from_fork)
> >
> >-ENTRY(ret_from_kernel_thread)
> >+SYM_CODE_START(ret_from_kernel_thread)
> > call schedule_tail
> > /* Call fn(arg) */
> >- la ra, ret_from_exception
> > move a0, s1
> >- jr s0
> >-ENDPROC(ret_from_kernel_thread)
> >-
> >+ jalr s0
> >+ move a0, sp /* pt_regs */
> >+ la ra, ret_from_exception
> >+ tail syscall_exit_to_user_mode
> >+SYM_CODE_END(ret_from_kernel_thread)
> >
> > /*
> > * Integer register context switch
> >@@ -533,7 +359,7 @@ ENDPROC(ret_from_kernel_thread)
> > * The value of a0 and a1 must be preserved by this function, as that's how
> > * arguments are passed to schedule_tail.
> > */
> >-ENTRY(__switch_to)
> >+SYM_FUNC_START(__switch_to)
> > /* Save context into prev->thread */
> > li a4, TASK_THREAD_RA
> > add a3, a0, a4
> >@@ -570,7 +396,7 @@ ENTRY(__switch_to)
> > /* The offset of thread_info in task_struct is zero. */
> > move tp, a1
> > ret
> >-ENDPROC(__switch_to)
> >+SYM_FUNC_END(__switch_to)
> >
> > #ifndef CONFIG_MMU
> > #define do_page_fault do_trap_unknown
> >@@ -579,7 +405,7 @@ ENDPROC(__switch_to)
> > .section ".rodata"
> > .align LGREG
> > /* Exception vector table */
> >-ENTRY(excp_vect_table)
> >+SYM_CODE_START(excp_vect_table)
> > RISCV_PTR do_trap_insn_misaligned
> > ALT_INSN_FAULT(RISCV_PTR do_trap_insn_fault)
> > RISCV_PTR do_trap_insn_illegal
> >@@ -588,7 +414,7 @@ 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_trap_ecall_u /* system call */
> > RISCV_PTR do_trap_ecall_s
> > RISCV_PTR do_trap_unknown
> > RISCV_PTR do_trap_ecall_m
> >@@ -598,11 +424,11 @@ ENTRY(excp_vect_table)
> > RISCV_PTR do_trap_unknown
> > RISCV_PTR do_page_fault /* store page fault */
> > excp_vect_table_end:
> >-END(excp_vect_table)
> >+SYM_CODE_END(excp_vect_table)
> >
> > #ifndef CONFIG_MMU
> >-ENTRY(__user_rt_sigreturn)
> >+SYM_CODE_START(__user_rt_sigreturn)
> > li a7, __NR_rt_sigreturn
> > scall
> >-END(__user_rt_sigreturn)
> >+SYM_CODE_END(__user_rt_sigreturn)
> > #endif
> >diff --git a/arch/riscv/kernel/head.h b/arch/riscv/kernel/head.h
> >index 726731ada534..a556fdaafed9 100644
> >--- a/arch/riscv/kernel/head.h
> >+++ b/arch/riscv/kernel/head.h
> >@@ -10,7 +10,6 @@
> >
> > extern atomic_t hart_lottery;
> >
> >-asmlinkage void do_page_fault(struct pt_regs *regs);
> > asmlinkage void __init setup_vm(uintptr_t dtb_pa);
> > #ifdef CONFIG_XIP_KERNEL
> > asmlinkage void __init __copy_data(void);
> >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 bfb2afa4135f..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;
> >
> >@@ -311,29 +312,3 @@ static void do_signal(struct pt_regs *regs)
> > */
> > restore_saved_sigmask();
> > }
> >-
> >-/*
> >- * Handle any pending work on the resume-to-userspace path, as indicated by
> >- * _TIF_WORK_MASK. Entered from assembly with IRQs off.
> >- */
> >-asmlinkage __visible void do_work_pending(struct pt_regs *regs,
> >- unsigned long thread_info_flags)
> >-{
> >- do {
> >- if (thread_info_flags & _TIF_NEED_RESCHED) {
> >- schedule();
> >- } else {
> >- local_irq_enable();
> >- 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);
> >- }
> >- local_irq_disable();
> >- thread_info_flags = read_thread_flags();
> >- } while (thread_info_flags & _TIF_WORK_MASK);
> >-}
> >diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> >index 96ec76c54ff2..69d619ddbcd5 100644
> >--- a/arch/riscv/kernel/traps.c
> >+++ b/arch/riscv/kernel/traps.c
> >@@ -17,12 +17,14 @@
> > #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>
> > #include <asm/csr.h>
> > #include <asm/processor.h>
> > #include <asm/ptrace.h>
> >+#include <asm/syscall.h>
> > #include <asm/thread_info.h>
> >
> > int show_unhandled_signals = 1;
> >@@ -99,10 +101,18 @@ 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 state = irqentry_nmi_enter(regs); \
> >+ do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
> >+ irqentry_nmi_exit(regs, state); \
> >+ } \
> > }
> >
> > DO_ERROR_INFO(do_trap_unknown,
> >@@ -124,26 +134,50 @@ DO_ERROR_INFO(do_trap_store_misaligned,
> > int handle_misaligned_load(struct pt_regs *regs);
> > int handle_misaligned_store(struct pt_regs *regs);
> >
> >-asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs)
> >+asmlinkage __visible __trap_section void 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 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, state);
> >+ }
> > }
> >
> >-asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs)
> >+asmlinkage __visible __trap_section void 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))
> >+

--
Best Regards
Guo Ren