* [PATCH 1/1] alpha: enable GENERIC_ENTRY
2026-09-02 18:38 [PATCH v5 0/1] alpha: enable GENERIC_ENTRY Magnus Lindholm
@ 2026-09-02 18:38 ` Magnus Lindholm
0 siblings, 0 replies; 2+ messages in thread
From: Magnus Lindholm @ 2026-09-02 18:38 UTC (permalink / raw)
To: richard.henderson, mattst88, linux-kernel, linux-alpha
Cc: glaubitz, mcree, Magnus Lindholm
Wire Alpha into the generic entry code for syscall entry/exit and
return-to-user handling, while keeping the low-level PALcode return paths
Alpha-specific.
Move most of the syscall entry/exit logic out of entSys and into C helpers
built around the generic entry API. Syscall entry now uses
syscall_enter_from_user_mode(), records Alpha-local syscall metadata in
thread_info, handles the ptrace/seccomp skip decision, and selects the
syscall table target in C. The final target call remains in entry.S so
Alpha can preserve its existing syscall ABI and assembly syscall-table
wrappers.
On return from syscalls, finish Alpha's r0/r19 result encoding and
skipped-syscall restart handling in C before calling
syscall_exit_to_user_mode(). Non-syscall returns to user mode use a
separate alpha_exit_to_user_mode() helper, which disables interrupts,
runs irqentry_exit_to_user_mode_prepare(), and then enters the common
exit_to_user_mode() path.
Keep the remaining PALcode restore handling in assembly. In particular,
kernel-mode returns still need Alpha-specific lockdep IRQ-state annotation
based on the saved processor status, while user-mode returns are handed to
the generic exit-to-user code.
Add the generic-entry support bits needed by common code, including
thread_info.syscall_work, syscall trace support, ptrace sysemu request
numbers, and arch_syscall_is_vdso_sigreturn().
This has been tested by booting Alpha with GENERIC_ENTRY enabled, checking
lockdep IRQ-state accounting, running fork/clone-heavy package builds, and
running the seccomp as well as strace test suites.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
arch/alpha/Kconfig | 2 +
arch/alpha/include/asm/entry-common.h | 14 ++
arch/alpha/include/asm/ptrace.h | 14 +-
arch/alpha/include/asm/stacktrace.h | 20 ++
arch/alpha/include/asm/syscall.h | 11 +-
arch/alpha/include/asm/thread_info.h | 30 +--
arch/alpha/kernel/asm-offsets.c | 5 +
arch/alpha/kernel/entry.S | 322 +++++++-------------------
arch/alpha/kernel/irq_alpha.c | 14 +-
arch/alpha/kernel/proto.h | 9 +-
arch/alpha/kernel/ptrace.c | 130 +++++------
arch/alpha/kernel/signal.c | 164 ++++++++++---
12 files changed, 370 insertions(+), 365 deletions(-)
create mode 100644 arch/alpha/include/asm/entry-common.h
create mode 100644 arch/alpha/include/asm/stacktrace.h
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index e53ef2d88463..51a7391869dd 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -2,6 +2,8 @@
config ALPHA
bool
default y
+ select GENERIC_ENTRY
+ select HAVE_SYSCALL_TRACEPOINTS
select ARCH_32BIT_USTAT_F_TINODE
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DMA_OPS if PCI
diff --git a/arch/alpha/include/asm/entry-common.h b/arch/alpha/include/asm/entry-common.h
new file mode 100644
index 000000000000..a811c73454d2
--- /dev/null
+++ b/arch/alpha/include/asm/entry-common.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ARCH_ALPHA_ENTRY_COMMON_H
+#define ARCH_ALPHA_ENTRY_COMMON_H
+
+#include <asm/stacktrace.h> /* For on_thread_stack() */
+#include <asm/syscall.h>
+
+#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work
+
+static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
+ unsigned long ti_work)
+{
+}
+#endif
diff --git a/arch/alpha/include/asm/ptrace.h b/arch/alpha/include/asm/ptrace.h
index 8e0a589e2d15..430e8dc27ff7 100644
--- a/arch/alpha/include/asm/ptrace.h
+++ b/arch/alpha/include/asm/ptrace.h
@@ -3,7 +3,7 @@
#define _ASMAXP_PTRACE_H
#include <uapi/asm/ptrace.h>
-
+#include <asm/irqflags.h>
#define arch_has_single_step() (1)
#define user_mode(regs) (((regs)->ps & 8) != 0)
@@ -17,7 +17,9 @@
#define current_pt_regs() \
((struct pt_regs *) ((char *)current_thread_info() + 2*PAGE_SIZE) - 1)
-#define force_successful_syscall_return() (current_pt_regs()->r0 = 0)
+#define force_successful_syscall_return() \
+ (current_thread_info()->syscall_meta \
+ |= ALPHA_SYSCALL_META_FORCE_SUCCESS)
static inline unsigned long regs_return_value(struct pt_regs *regs)
{
@@ -31,4 +33,12 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs)
return regs->usp;
}
+static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)
+{
+ return arch_irqs_disabled_flags(regs->ps);
+}
+
+/* Syscall emulation defines */
+#define PTRACE_SYSEMU 0x1d
+#define PTRACE_SYSEMU_SINGLESTEP 0x1e
#endif
diff --git a/arch/alpha/include/asm/stacktrace.h b/arch/alpha/include/asm/stacktrace.h
new file mode 100644
index 000000000000..f006d6f00fd0
--- /dev/null
+++ b/arch/alpha/include/asm/stacktrace.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ALPHA_STACKTRACE_H
+#define _ASM_ALPHA_STACKTRACE_H
+
+#include <linux/compiler_attributes.h>
+#include <linux/types.h>
+
+#include <asm/current.h>
+#include <asm/processor.h>
+#include <asm/thread_info.h>
+
+static __always_inline bool on_thread_stack(void)
+{
+ unsigned long base = (unsigned long)current->stack;
+ unsigned long sp = (unsigned long)current_stack_pointer;
+
+ return !((base ^ sp) & ~(THREAD_SIZE - 1));
+}
+
+#endif /* _ASM_ALPHA_STACKTRACE_H */
diff --git a/arch/alpha/include/asm/syscall.h b/arch/alpha/include/asm/syscall.h
index 1e78cbd46faf..c1394910f584 100644
--- a/arch/alpha/include/asm/syscall.h
+++ b/arch/alpha/include/asm/syscall.h
@@ -8,6 +8,8 @@
#include <linux/types.h>
#include <asm/ptrace.h>
+extern void *sys_call_table[];
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_ALPHA;
@@ -104,10 +106,17 @@ static inline void syscall_set_return_value(struct task_struct *task,
}
/* Restore the original syscall nr after seccomp/ptrace modified regs->r1. */
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
- regs->r1 = regs->r2;
+ unsigned long nr = task_thread_info(task)->syscall_saved_nr;
+
+ regs->r1 = nr;
}
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+ return false;
+}
#endif /* _ASM_ALPHA_SYSCALL_H */
diff --git a/arch/alpha/include/asm/thread_info.h b/arch/alpha/include/asm/thread_info.h
index 1552ecca8520..d781ac79106d 100644
--- a/arch/alpha/include/asm/thread_info.h
+++ b/arch/alpha/include/asm/thread_info.h
@@ -12,16 +12,21 @@
#endif
#ifndef __ASSEMBLER__
+
struct thread_info {
struct pcb_struct pcb; /* palcode state */
struct task_struct *task; /* main task structure */
- unsigned int flags; /* low level flags */
+ unsigned long flags; /* low level flags */
+ unsigned long syscall_work; /* SYSCALL_WORK_* flags */
unsigned int ieee_state; /* see fpu.h */
unsigned cpu; /* current CPU */
- int preempt_count; /* 0 => preemptable, <0 => BUG */
+ int preempt_count; /* 0 => preemptable, <0 => BUG */
unsigned int status; /* thread-synchronous flags */
+ unsigned long syscall_saved_r19;
+ unsigned long syscall_meta;
+ unsigned long syscall_saved_nr;
int bpt_nsaved;
unsigned long bpt_addr[2]; /* breakpoint handling */
@@ -50,6 +55,9 @@ register unsigned long *current_stack_pointer __asm__ ("$30");
#define THREAD_SIZE_ORDER 1
#define THREAD_SIZE (2*PAGE_SIZE)
+#define ALPHA_SYSCALL_META_SKIP 0x2
+#define ALPHA_SYSCALL_META_FORCE_SUCCESS 0x4
+
/*
* Thread information flags:
* - these are process state flags and used from assembly
@@ -68,6 +76,7 @@ register unsigned long *current_stack_pointer __asm__ ("$30");
#define TIF_SECCOMP 6 /* seccomp syscall filtering active */
#define TIF_SYSCALL_TRACEPOINT 7 /* syscall tracepoint instrumentation */
#define TIF_DIE_IF_KERNEL 9 /* dik recursion lock */
+#define TIF_UPROBE 10 /* uprobe breakpoint or singlestep */
#define TIF_MEMDIE 13 /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG 14 /* idle is polling for TIF_NEED_RESCHED */
@@ -80,22 +89,7 @@ register unsigned long *current_stack_pointer __asm__ ("$30");
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
-
-/*
- * Work to do on syscall entry (in entry.S).
- * If you want this to exactly mirror what entry.S checks, keep it aligned
- * with the mask used before branching to syscall_trace_enter().
- */
-#ifdef CONFIG_AUDITSYSCALL
-# define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP \
- | _TIF_SYSCALL_TRACEPOINT)
-#else
-# define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
-#endif
-
-/* Work to do on interrupt/exception return. */
-#define _TIF_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
- _TIF_NOTIFY_RESUME | _TIF_NOTIFY_SIGNAL)
+#define _TIF_UPROBE (1 << TIF_UPROBE)
#define TS_UAC_NOPRINT 0x0001 /* ! Preserve the following three */
#define TS_UAC_NOFIX 0x0002 /* ! flags as they match */
diff --git a/arch/alpha/kernel/asm-offsets.c b/arch/alpha/kernel/asm-offsets.c
index 1d3bfca319ae..c89792c86044 100644
--- a/arch/alpha/kernel/asm-offsets.c
+++ b/arch/alpha/kernel/asm-offsets.c
@@ -22,6 +22,7 @@ static void __used foo(void)
DEFINE(SP_OFF, offsetof(struct pt_regs, ps));
DEFINE(SIZEOF_PT_REGS, sizeof(struct pt_regs));
+ DEFINE(TI_SYSCALL_META, offsetof(struct thread_info, syscall_meta));
BLANK();
DEFINE(SWITCH_STACK_SIZE, sizeof(struct switch_stack));
@@ -30,4 +31,8 @@ static void __used foo(void)
DEFINE(HAE_CACHE, offsetof(struct alpha_machine_vector, hae_cache));
DEFINE(HAE_REG, offsetof(struct alpha_machine_vector, hae_register));
DEFINE(PT_REGS_USP, offsetof(struct pt_regs, usp));
+
+ DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
+ DEFINE(TI_SYSCALL_WORK, offsetof(struct thread_info, syscall_work));
+ DEFINE(TI_STATUS, offsetof(struct thread_info, status));
}
diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
index 9f2608de2544..bfa116d455fb 100644
--- a/arch/alpha/kernel/entry.S
+++ b/arch/alpha/kernel/entry.S
@@ -36,67 +36,10 @@
.size \func, . - \func
.endm
-/*
- * SYSCALL_SKIP_RETURN_RESTART_GATE
- *
- * Used when syscall dispatch is skipped (seccomp/ptrace injected nr=-1).
- * - Ensure we never return r0==-1 with a3==0 (success); convert to ENOSYS.
- * - Gate whether syscall restart is allowed by preserving restart context
- * only for ERESTART* returns. Result:
- * $26 = 0 => restart allowed
- * $26 = 1 => restart NOT allowed
- * $18 = preserved syscall nr (regs->r2) if restart allowed, else 0
- */
-.macro SYSCALL_SKIP_RETURN_RESTART_GATE
- /* Fix up invalid "-1 success" return state. */
- ldq $19, 72($sp) /* a3 */
- bne $19, 1f /* already error => skip fixup */
-
- ldq $20, 0($sp) /* r0 */
- lda $21, -1($31)
- cmpeq $20, $21, $22
- beq $22, 1f /* r0 != -1 => skip fixup */
-
-
- lda $20, ENOSYS($31)
- stq $20, 0($sp) /* r0 = ENOSYS */
- lda $19, 1($31)
- stq $19, 72($sp) /* a3 = 1 */
-1:
- /* Restart gating: success is never restartable here. */
- ldq $19, 72($sp) /* a3 */
- beq $19, 3f /* success => not restartable */
-
- ldq $20, 0($sp) /* r0 (positive errno if a3==1) */
- lda $21, ERESTARTSYS($31)
- cmpeq $20, $21, $22
- bne $22, 2f
- lda $21, ERESTARTNOINTR($31)
- cmpeq $20, $21, $22
- bne $22, 2f
- lda $21, ERESTARTNOHAND($31)
- cmpeq $20, $21, $22
- bne $22, 2f
- lda $21, ERESTART_RESTARTBLOCK($31)
- cmpeq $20, $21, $22
- bne $22, 2f
-
-3: /* Not a restart code (or success) => restart NOT allowed. */
- addq $31, 1, $26 /* $26=1 => restart NOT allowed */
- mov 0, $18
- br 4f
-
-2: /* Restart allowed. */
- ldq $18, 16($sp) /* preserved syscall nr (regs->r2) */
- mov $31, $26 /* $26=0 => restart allowed */
- br 4f
-4:
-.endm
-
-.macro LOCKDEP_HARDIRQS_ON_RESTORE
+.macro LOCKDEP_HARDIRQS_ON_RESTORE psreg
#ifdef CONFIG_PROVE_LOCKING
/* a0 = saved PS */
- ldq $16, SP_OFF($sp)
+ ldq $16, \psreg
/* a1 = callsite IP for lockdep */
lda $17, 1f
@@ -248,7 +191,7 @@
CFI_START_OSF_FRAME entInt
SAVE_ALL
lda $8, 0x3fff
- lda $26, ret_from_sys_call
+ lda $26, ret_from_exception
bic $sp, $8, $8
mov $sp, $19
jsr $31, do_entInt
@@ -257,7 +200,7 @@ CFI_END_OSF_FRAME entInt
CFI_START_OSF_FRAME entArith
SAVE_ALL
lda $8, 0x3fff
- lda $26, ret_from_sys_call
+ lda $26, ret_from_exception
bic $sp, $8, $8
mov $sp, $18
jsr $31, do_entArith
@@ -305,13 +248,13 @@ CFI_START_OSF_FRAME entMM
.cfi_restore $15
.cfi_adjust_cfa_offset -64
/* finish up the syscall as normal. */
- br ret_from_sys_call
+ br ret_from_exception
CFI_END_OSF_FRAME entMM
CFI_START_OSF_FRAME entIF
SAVE_ALL
lda $8, 0x3fff
- lda $26, ret_from_sys_call
+ lda $26, ret_from_exception
bic $sp, $8, $8
mov $sp, $17
jsr $31, do_entIF
@@ -440,7 +383,7 @@ CFI_START_OSF_FRAME entUna
.cfi_restore $28
.cfi_restore $29
.cfi_adjust_cfa_offset -256
- LOCKDEP_HARDIRQS_ON_RESTORE
+ LOCKDEP_HARDIRQS_ON_RESTORE SP_OFF($sp)
call_pal PAL_rti
.align 4
@@ -487,18 +430,19 @@ entUnaUser:
.cfi_restore $14
.cfi_restore $15
.cfi_adjust_cfa_offset -64
- br ret_from_sys_call
+ br ret_from_exception
CFI_END_OSF_FRAME entUna
CFI_START_OSF_FRAME entDbg
SAVE_ALL
lda $8, 0x3fff
- lda $26, ret_from_sys_call
+ lda $26, ret_from_exception
bic $sp, $8, $8
mov $sp, $16
jsr $31, do_entDbg
CFI_END_OSF_FRAME entDbg
+
/*
* The system call entry point is special. Most importantly, it looks
* like a function call to userspace as far as clobbered registers. We
@@ -516,9 +460,7 @@ CFI_END_OSF_FRAME entDbg
* For seccomp/ptrace/generic syscall helpers we track the syscall
* number separately:
* - regs->r1: current (mutable) syscall number (may be changed or set to -1)
- * - regs->r2: original syscall number for restart/rollback
*
- * On entry PAL provides the syscall number in r0; copy it into r1/r2.
*/
.align 4
@@ -531,203 +473,117 @@ CFI_END_OSF_FRAME entDbg
.cfi_rel_offset $gp, 16
entSys:
SAVE_ALL
- ldq $1, 0($sp) /* syscall nr from saved r0 */
- stq $1, 8($sp) /* regs->r1 = shadow syscall nr */
- stq $1, 16($sp) /* regs->r2 = restart syscall nr */
- /* Syscalls always enter from user mode: snapshot USP into pt_regs->usp */
+ ldq $1, 0($sp) /* syscall nr from saved r0 */
+ stq $1, 8($sp) /* regs->r1 = shadow syscall nr */
+
mov $0, $8
call_pal PAL_rdusp
- stq $0, PT_REGS_USP($sp)
+ stq $0, PT_REGS_USP($sp)
mov $8, $0
-
lda $8, 0x3fff
bic $sp, $8, $8
- lda $4, NR_syscalls($31)
+
stq $16, SP_OFF+24($sp)
- lda $5, sys_call_table
- lda $27, sys_ni_syscall
- cmpult $0, $4, $4
- ldl $3, TI_FLAGS($8)
stq $17, SP_OFF+32($sp)
- s8addq $0, $5, $5
stq $18, SP_OFF+40($sp)
- .cfi_rel_offset $16, SP_OFF+24
- .cfi_rel_offset $17, SP_OFF+32
- .cfi_rel_offset $18, SP_OFF+40
- lda $6, _TIF_SYSCALL_WORK
- and $3, $6, $3
- bne $3, strace
- beq $4, 1f
- ldq $27, 0($5)
-1: ldq $0, 8($sp) /* syscall nr shadow (regs->r1) */
+ mov $0, $1
+ lda $16, 7
+ call_pal PAL_swpipl
+ mov $1, $0
+ mov $sp, $16
+ mov $0, $17 /* pv = selected syscall function */
+
+ DO_SWITCH_STACK
+ jsr $26, alpha_syscall_enter_select
+ ldgp $gp, 0($26)
+ UNDO_SWITCH_STACK
+
+ /*
+ * C returned syscall function pointer in $0.
+ * It also stored SKIP in TI_SYSCALL_META if dispatch is skipped.
+ */
+ lda $8, 0x3fff
+ bic $sp, $8, $8
+ ldq $3, TI_SYSCALL_META($8)
+ lda $6, ALPHA_SYSCALL_META_SKIP
+ and $3, $6, $6
+ bne $6, skip_dispatch
+
+
+ mov $0, $27
+ ldq $16, SP_OFF+24($sp)
+ ldq $17, SP_OFF+32($sp)
+ ldq $18, SP_OFF+40($sp)
+ ldq $19, 72($sp)
+ ldq $20, 80($sp)
+ ldq $21, 88($sp)
jsr $26, ($27), sys_ni_syscall
ldgp $gp, 0($26)
- blt $0, $syscall_error /* the call failed */
-$ret_success:
- stq $0, 0($sp)
- stq $31, 72($sp) /* a3=0 => no error */
- .align 4
- .globl ret_from_sys_call
-ret_from_sys_call:
- cmovne $26, 0, $18 /* $18 = 0 => non-restartable */
- ldq $0, SP_OFF($sp)
- and $0, 8, $0
- beq $0, ret_to_kernel
-ret_to_user:
- /* Make sure need_resched and sigpending don't change between
- sampling and the rti. */
- lda $16, 7
- call_pal PAL_swpipl
- ldl $17, TI_FLAGS($8)
- and $17, _TIF_WORK_MASK, $2
- bne $2, work_pending
+skip_dispatch:
+ mov $0, $17 /* raw ret; ignored if SKIP is set */
+ mov $sp, $16 /* regs */
+
+ DO_SWITCH_STACK
+ jsr $26, alpha_finish_syscall_to_user_mode
+ ldgp $gp, 0($26)
+ UNDO_SWITCH_STACK
+
restore_all:
+ lda $8, 0x3fff
+ bic $sp, $8, $8
ldl $2, TI_STATUS($8)
and $2, TS_SAVED_FP | TS_RESTORE_FP, $3
bne $3, restore_fpu
restore_other:
.cfi_remember_state
- LOCKDEP_HARDIRQS_ON_RESTORE
RESTORE_ALL
call_pal PAL_rti
-ret_to_kernel:
- .cfi_restore_state
- lda $16, 7
- call_pal PAL_swpipl
- br restore_other
-
- .align 3
-$syscall_error:
- /* Restart syscall nr comes from saved r2 (preserved even if r0 overwritten). */
- ldq $18, 16($sp) /* old syscall nr for restart */
-
- ldq $19, 72($sp) /* .. and this a3 */
- subq $31, $0, $0 /* with error in v0 */
- addq $31, 1, $1 /* set a3 for errno return */
- stq $0, 0($sp)
- mov $31, $26 /* tell "ret_from_sys_call" we can restart */
- stq $1, 72($sp) /* a3 for return */
- br ret_from_sys_call
-
-/*
- * Do all cleanup when returning from all interrupts and system calls.
- *
- * Arguments:
- * $8: current.
- * $17: TI_FLAGS.
- * $18: The old syscall number, or zero if this is not a return
- * from a syscall that errored and is possibly restartable.
- * $19: The old a3 value
- */
-
- .align 4
- .type work_pending, @function
-work_pending:
- and $17, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL, $2
- bne $2, $work_notifysig
-
-$work_resched:
- /*
- * We can get here only if we returned from syscall without SIGPENDING
- * or got through work_notifysig already. Either case means no syscall
- * restarts for us, so let $18 and $19 burn.
- */
- jsr $26, alpha_schedule_user_work
- mov 0, $18
- br ret_to_user
+ret_to_user_from_syscall:
+ lda $8, 0x3fff
+ bic $sp, $8, $8
-$work_notifysig:
mov $sp, $16
DO_SWITCH_STACK
- jsr $26, do_work_pending
+ jsr $26, alpha_syscall_exit_to_user_mode
+ ldgp $gp, 0($26)
UNDO_SWITCH_STACK
br restore_all
-/*
- * PTRACE syscall handler
- */
-
.align 4
- .type strace, @function
-strace:
- /* set up signal stack, call syscall_trace */
- // NB: if anyone adds preemption, this block will need to be protected
- ldl $1, TI_STATUS($8)
- and $1, TS_SAVED_FP, $3
- or $1, TS_SAVED_FP, $2
- bne $3, 1f
- stl $2, TI_STATUS($8)
- bsr $26, __save_fpu
-1:
- DO_SWITCH_STACK
- jsr $26, syscall_trace_enter /* returns the syscall number */
- UNDO_SWITCH_STACK
-
- stq $0, 8($sp) /* regs->r1 = shadow syscall nr */
-
- /* get the arguments back.. */
- ldq $16, SP_OFF+24($sp)
- ldq $17, SP_OFF+32($sp)
- ldq $18, SP_OFF+40($sp)
- ldq $19, 72($sp)
- ldq $20, 80($sp)
- ldq $21, 88($sp)
+ .globl ret_from_sys_call
+ret_from_sys_call:
+ ldq $0, SP_OFF($sp)
+ and $0, 8, $0
+ beq $0, ret_to_kernel
+ br ret_to_user_from_syscall
- /* nr == -1: internal skip-dispatch or userspace syscall(-1)? */
- lda $6, -1($31)
- cmpeq $0, $6, $6
- bne $6, $strace_skip_call /* nr == -1 => dispatch */
-
- /* get the system call pointer.. */
- lda $1, NR_syscalls($31)
- lda $2, sys_call_table
- lda $27, sys_ni_syscall
- cmpult $0, $1, $1
- s8addq $0, $2, $2
- beq $1, 1f
- ldq $27, 0($2)
-1: jsr $26, ($27), sys_gettimeofday
-ret_from_straced:
- ldgp $gp, 0($26)
+ret_from_exception:
+ ldq $0, SP_OFF($sp)
+ and $0, 8, $0
+ beq $0, ret_to_kernel
+ br ret_to_user_from_exception
- /* check return.. */
- blt $0, $strace_error /* the call failed */
-$strace_success:
- stq $31, 72($sp) /* a3=0 => no error */
- stq $0, 0($sp) /* save return value */
+ret_to_user_from_exception:
-$strace_skip_call:
- SYSCALL_SKIP_RETURN_RESTART_GATE
+ mov $sp, $16
DO_SWITCH_STACK
- jsr $26, syscall_trace_leave
+ jsr $26, alpha_exit_to_user_mode
+ ldgp $gp, 0($26)
UNDO_SWITCH_STACK
- br $31, ret_from_sys_call
-
- .align 3
-$strace_error:
- ldq $18, 16($sp) /* restart syscall nr */
- ldq $19, 72($sp) /* .. and this a3 */
-
- subq $31, $0, $0 /* with error in v0 */
- addq $31, 1, $1 /* set a3 for errno return */
- stq $0, 0($sp)
- stq $1, 72($sp) /* a3 for return */
+ br restore_all
- DO_SWITCH_STACK
- mov $18, $9 /* save old syscall number */
- mov $19, $10 /* save old a3 */
- jsr $26, syscall_trace_leave
- mov $9, $18
- mov $10, $19
- UNDO_SWITCH_STACK
+ret_to_kernel:
+ .cfi_restore_state
+ lda $16, 7
+ call_pal PAL_swpipl
+ LOCKDEP_HARDIRQS_ON_RESTORE SP_OFF($sp)
+ br restore_other
- mov $31, $26 /* tell "ret_from_sys_call" we can restart */
- br ret_from_sys_call
CFI_END_OSF_FRAME entSys
/*
@@ -815,7 +671,6 @@ restore_fpu:
br restore_other
#undef V
-\f
/*
* The meat of the context switch code.
*/
@@ -851,7 +706,7 @@ alpha_switch_to:
.align 4
.ent ret_from_fork
ret_from_fork:
- lda $26, ret_to_user
+ lda $26, ret_to_user_from_exception
mov $17, $16
jmp $31, schedule_tail
.end ret_from_fork
@@ -868,7 +723,7 @@ ret_from_kernel_thread:
mov $9, $27
mov $10, $16
jsr $26, ($9)
- br $31, ret_to_user
+ br $31, ret_to_user_from_exception
.end ret_from_kernel_thread
\f
@@ -910,12 +765,9 @@ fork_like clone3
.ent sys_\name
sys_\name:
.prologue 0
- lda $9, ret_from_straced
- cmpult $26, $9, $9
+ mov $sp, $10
lda $sp, -SWITCH_STACK_SIZE($sp)
jsr $26, do_\name
- bne $9, 1f
- jsr $26, syscall_trace_leave
1: br $1, undo_switch_stack
br ret_from_sys_call
.end sys_\name
diff --git a/arch/alpha/kernel/irq_alpha.c b/arch/alpha/kernel/irq_alpha.c
index 1b799aafb7dc..f90ff898a71a 100644
--- a/arch/alpha/kernel/irq_alpha.c
+++ b/arch/alpha/kernel/irq_alpha.c
@@ -116,20 +116,24 @@ void notrace lockdep_on_restore(unsigned long ps,
unsigned long ip)
{
#ifdef CONFIG_PROVE_LOCKING
- /* Restoring IPL==7 means interrupts remain disabled. */
+ /*
+ * If PAL_rti will restore IPL == 7, IRQs remain disabled.
+ * There is no hardirqs-on transition to annotate.
+ */
if ((ps & 7) == 7)
return;
/*
- * If hardware IRQs are already enabled here, then emitting a
- * hardirqs-on transition is redundant.
+ * This helper is meant to run before PAL_rti, after entry.S has
+ * forced IPL to 7. If IRQs are already enabled, do not emit a
+ * fake transition.
*/
if (!irqs_disabled())
return;
/*
- * Only emit the transition if lockdep currently believes
- * hardirqs are off.
+ * Only emit an ON transition if lockdep currently tracks hardirqs
+ * as off.
*/
if (lockdep_hardirqs_enabled())
return;
diff --git a/arch/alpha/kernel/proto.h b/arch/alpha/kernel/proto.h
index 9b262ef09a3a..f138bd494628 100644
--- a/arch/alpha/kernel/proto.h
+++ b/arch/alpha/kernel/proto.h
@@ -2,6 +2,7 @@
#include <linux/interrupt.h>
#include <linux/screen_info.h>
#include <linux/io.h>
+#include <asm/ptrace.h>
/* Prototypes of functions used across modules here in this directory. */
@@ -164,16 +165,18 @@ extern void pcibios_claim_one_bus(struct pci_bus *);
/* ptrace.c */
extern int ptrace_set_bpt (struct task_struct *child);
extern int ptrace_cancel_bpt (struct task_struct *child);
-extern void syscall_trace_leave(void);
-extern unsigned long syscall_trace_enter(void);
/* signal.c */
struct sigcontext;
extern void do_sigreturn(struct sigcontext __user *);
struct rt_sigframe;
extern void do_rt_sigreturn(struct rt_sigframe __user *);
-extern void do_work_pending(struct pt_regs *, unsigned long, unsigned long, unsigned long);
extern void alpha_schedule_user_work(void);
+extern void do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19);
+extern void alpha_syscall_exit_to_user_mode(struct pt_regs *regs);
+extern void alpha_exit_to_user_mode(struct pt_regs *regs);
+extern void alpha_finish_syscall_to_user_mode(struct pt_regs *regs, long ret);
+extern unsigned long alpha_syscall_enter_select(struct pt_regs *regs, long syscall);
/* traps.c */
extern void dik_show_regs(struct pt_regs *regs, unsigned long *r9_15);
diff --git a/arch/alpha/kernel/ptrace.c b/arch/alpha/kernel/ptrace.c
index fc8f6cedbb28..e1d8c2f69688 100644
--- a/arch/alpha/kernel/ptrace.c
+++ b/arch/alpha/kernel/ptrace.c
@@ -134,18 +134,44 @@ get_reg_addr(struct task_struct * task, unsigned long regno)
/*
* Get contents of register REGNO in task TASK.
*/
-static unsigned long
-get_reg(struct task_struct * task, unsigned long regno)
+
+static bool
+valid_regno(unsigned long regno)
+{
+ return regno <= 65;
+}
+
+static long
+get_reg(struct task_struct *task, unsigned long regno)
{
- /* Special hack for fpcr -- combine hardware and software bits. */
+ unsigned long *addr;
+
+ if (!valid_regno(regno))
+ return -EIO;
+
+ /*
+ * Special hack for fpcr -- combine hardware and software bits.
+ */
if (regno == 63) {
- unsigned long fpcr = *get_reg_addr(task, regno);
- unsigned long swcr
- = task_thread_info(task)->ieee_state & IEEE_SW_MASK;
+ unsigned long fpcr;
+ unsigned long swcr;
+
+ addr = get_reg_addr(task, regno);
+ if (!addr)
+ return -EIO;
+
+ fpcr = *addr;
+ swcr = task_thread_info(task)->ieee_state & IEEE_SW_MASK;
swcr = swcr_update_status(swcr, fpcr);
+
return fpcr | swcr;
}
- return *get_reg_addr(task, regno);
+
+ addr = get_reg_addr(task, regno);
+ if (!addr)
+ return -EIO;
+
+ return *addr;
}
static void alpha_elf_fpregs_get(struct task_struct *target,
@@ -271,14 +297,17 @@ static void alpha_elf_gregs_set(struct task_struct *child,
pt->r19 = 1;
}
-
-/*
- * Write contents of register REGNO in task TASK.
- */
static int
put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
{
struct pt_regs *regs = task_pt_regs(task);
+ unsigned long *addr;
+ unsigned long old_r0 = regs->r0;
+
+ if (regno == 31)
+ return 0;
+ if (!valid_regno(regno))
+ return -EIO;
if (regno == 63) {
task_thread_info(task)->ieee_state
@@ -287,24 +316,30 @@ put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
data = (data & FPCR_DYN_MASK) | ieee_swcr_to_fpcr(data);
}
- *get_reg_addr(task, regno) = data;
+ addr = get_reg_addr(task, regno);
+ if (!addr)
+ return -EIO;
+
+ *addr = data;
/*
* Alpha historically exposes r0/v0 as the syscall number at a
* syscall-entry stop. The generic-entry conversion keeps the
- * mutable syscall number in regs->r1, so old ptrace users such
- * as strace that skip a syscall by poking r0 to -1 must also
- * update the internal shadow syscall number.
- *
- * Do not mirror other r0 writes. strace later pokes r0 to the
- * injected return value, e.g. 42, while r1 must remain -1.
+ * mutable syscall number in regs->r1.
*/
- if (regno == 0 && data == (unsigned long)-1) {
+ if (regno == 0 && regs->r1 == old_r0 &&
+ (data == (unsigned long)-1 ||
+ (regs->r19 == 0 && data < NR_syscalls))) {
regs->r1 = data;
- regs->r19 = 0;
- }
+ /*
+ * Keep the skip path looking like a clean entry-side syscall
+ * rewrite. Do not touch r19 for ordinary syscall substitution.
+ */
+ if (data == (unsigned long)-1)
+ regs->r19 = 0;
+ }
return 0;
}
@@ -435,25 +470,24 @@ long arch_ptrace(struct task_struct *child, long request,
switch (request) {
/* When I and D space are separate, these will need to be fixed. */
- case PTRACE_PEEKTEXT: /* read word at location addr. */
+ case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
copied = ptrace_access_vm(child, addr, &tmp, sizeof(tmp),
FOLL_FORCE);
ret = -EIO;
if (copied != sizeof(tmp))
break;
-
force_successful_syscall_return();
ret = tmp;
break;
- /* Read register number ADDR. */
case PTRACE_PEEKUSR:
- force_successful_syscall_return();
ret = get_reg(child, addr);
- DBG(DBG_MEM, ("peek $%lu->%#lx\n", addr, ret));
- break;
+ if (ret == -EIO)
+ break;
+ force_successful_syscall_return();
+ break;
/* When I and D space are separate, this will have to be fixed. */
case PTRACE_POKETEXT: /* write the word at location addr. */
case PTRACE_POKEDATA:
@@ -471,47 +505,6 @@ long arch_ptrace(struct task_struct *child, long request,
return ret;
}
-asmlinkage unsigned long syscall_trace_enter(void)
-{
- struct pt_regs *regs = current_pt_regs();
-
- if (test_thread_flag(TIF_SYSCALL_TRACE) &&
- !ptrace_report_syscall_permit_entry(regs)) {
- syscall_set_nr(current, regs, -1);
- if (regs->r19 == 0 && regs->r0 == (unsigned long)-1)
- syscall_set_return_value(current, regs, -ENOSYS, 0);
- return -1UL;
- }
-
- /*
- * Do the secure computing after ptrace; failures should be fast.
- * If this fails, seccomp may already have set up the return value
- * (e.g. SECCOMP_RET_ERRNO / TRACE).
- */
- if (!seccomp_permit_syscall()) {
- if (regs->r19 == 0 && regs->r0 == (unsigned long)-1)
- syscall_set_return_value(current, regs, -ENOSYS, 0);
- syscall_set_nr(current, regs, -1);
- return -1UL;
- }
-
-#ifdef CONFIG_AUDITSYSCALL
- audit_syscall_entry(syscall_get_nr(current, regs),
- regs->r16, regs->r17, regs->r18, regs->r19);
-#endif
- return syscall_get_nr(current, regs);
-}
-
-
-
-asmlinkage void
-syscall_trace_leave(void)
-{
- audit_syscall_exit(current_pt_regs());
- if (test_thread_flag(TIF_SYSCALL_TRACE))
- ptrace_report_syscall_exit(current_pt_regs(), 0);
-}
-
/*
* Minimal regset support for Alpha.
*
@@ -522,7 +515,6 @@ syscall_trace_leave(void)
* regset_get should return 0 on success. So call dump_elf_thread()
* directly and return membuf_write()'s result.
*/
-
static int alpha_regset_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index ce40a49b8496..0c55a7554d63 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -27,10 +27,9 @@
#include <linux/uaccess.h>
#include <asm/sigcontext.h>
#include <asm/ucontext.h>
-
+#include <linux/entry-common.h>
#include "proto.h"
-
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
@@ -41,14 +40,6 @@ asmlinkage void ret_from_sys_call(void);
* The OSF/1 sigprocmask calling sequence is different from the
* C sigprocmask() sequence..
*/
-
-asmlinkage void alpha_schedule_user_work(void)
-{
- local_irq_enable();
- schedule();
- local_irq_disable();
-}
-
SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
{
sigset_t oldmask;
@@ -465,6 +456,7 @@ syscall_restart(unsigned long r0, unsigned long r19,
fallthrough;
case ERESTARTNOINTR:
regs->r0 = r0; /* reset v0 and a3 and replay syscall */
+ regs->r1 = r0;
regs->r19 = r19;
regs->pc -= 4;
break;
@@ -488,7 +480,7 @@ syscall_restart(unsigned long r0, unsigned long r19,
* restart. "r0" is also used as an indicator whether we can restart at
* all (if we get here from anything but a syscall return, it will be 0)
*/
-static void
+void
do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
{
unsigned long single_stepping = ptrace_cancel_bpt(current);
@@ -511,12 +503,14 @@ do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
case ERESTARTNOINTR:
/* Reset v0 and a3 and replay syscall. */
regs->r0 = r0;
+ regs->r1 = r0;
regs->r19 = r19;
regs->pc -= 4;
break;
case ERESTART_RESTARTBLOCK:
/* Set v0 to the restart_syscall and replay */
regs->r0 = __NR_restart_syscall;
+ regs->r1 = __NR_restart_syscall;
regs->pc -= 4;
break;
}
@@ -527,27 +521,133 @@ do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
ptrace_set_bpt(current); /* re-set breakpoint */
}
-void
-do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
- unsigned long r0, unsigned long r19)
+asmlinkage void alpha_exit_to_user_mode(struct pt_regs *regs)
{
- do {
- if (thread_flags & _TIF_NEED_RESCHED) {
- local_irq_enable();
- schedule();
- } else {
- local_irq_enable();
- if (thread_flags & (_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)) {
- preempt_disable();
- save_fpu();
- preempt_enable();
- do_signal(regs, r0, r19);
- r0 = 0;
- } else {
- resume_user_mode_work(regs);
- }
+ local_irq_disable();
+ irqentry_exit_to_user_mode_prepare(regs);
+ exit_to_user_mode();
+}
+
+/*
+ * Syscall return reaches here after Alpha-specific r0/a3 result encoding.
+ * Delegate syscall-exit work and final exit-to-user handling to generic
+ * entry code; low-level PAL restore remains in assembly.
+ */
+asmlinkage void alpha_syscall_exit_to_user_mode(struct pt_regs *regs)
+{
+ syscall_exit_to_user_mode(regs);
+}
+
+void arch_do_signal_or_restart(struct pt_regs *regs)
+{
+ struct thread_info *ti = current_thread_info();
+
+ preempt_disable();
+ save_fpu();
+ preempt_enable();
+ do_signal(regs, ti->syscall_saved_nr, ti->syscall_saved_r19);
+}
+
+asmlinkage unsigned long
+alpha_syscall_enter_select(struct pt_regs *regs, long syscall)
+{
+ struct thread_info *ti = current_thread_info();
+ unsigned long saved_r0 = regs->r0;
+ unsigned long saved_r19 = regs->r19;
+ unsigned long fn = (unsigned long)sys_ni_syscall;
+ long nr = syscall;
+ bool permit;
+
+ ti->syscall_meta = 0;
+ ti->syscall_saved_nr = syscall;
+
+ if (!(ti->status & TS_SAVED_FP)) {
+ ti->status |= TS_SAVED_FP;
+ __save_fpu();
+ }
+
+ permit = syscall_enter_from_user_mode_randomize_stack(regs, &nr);
+
+ /*
+ * Alpha cannot preset the full -ENOSYS return state before generic
+ * entry handling, because r19 is still syscall argument 4 on the
+ * normal dispatch path. So provide the default -ENOSYS result only
+ * here, after we know no real syscall will be invoked, and only if
+ * entry work did not already change the return state.
+ */
+ if (unlikely(!permit || (unsigned long)nr >= NR_syscalls)) {
+ if (regs->r0 == saved_r0 && regs->r19 == saved_r19)
+ syscall_set_return_value(current, regs, -ENOSYS, 0);
+
+ ti->syscall_meta = ALPHA_SYSCALL_META_SKIP;
+ return fn; /* ignored by asm when SKIP is set */
+ }
+
+ instrumentation_begin();
+ {
+ unsigned long index;
+
+ index = array_index_nospec((unsigned long)nr, NR_syscalls);
+ fn = (unsigned long)sys_call_table[index];
+ }
+ instrumentation_end();
+
+ return fn;
+}
+
+asmlinkage noinstr void
+alpha_finish_syscall_to_user_mode(struct pt_regs *regs, long ret)
+{
+ struct thread_info *ti = current_thread_info();
+ unsigned long meta = ti->syscall_meta;
+
+ ti->syscall_meta = 0;
+ ti->syscall_saved_r19 = regs->r19;
+
+ instrumentation_begin();
+
+ if (meta & ALPHA_SYSCALL_META_SKIP) {
+ /*
+ * Skip-dispatch path: ptrace/seccomp may already have installed
+ * the return state in r0/r19. Preserve it unless the syscall was
+ * skipped with no explicit return value.
+ *
+ * Generic PTRACE_SET_SYSCALL_INFO changes only the syscall-number
+ * shadow, so r1 == -1 while r0 still contains the original Alpha
+ * syscall number. Legacy PTRACE_POKEUSR based skipping can leave
+ * r0 == -1 with a3/r19 still indicating success. Both represent
+ * an unhandled skipped syscall and should become ENOSYS/a3=1.
+ */
+ if (regs->r1 == (unsigned long)-1 &&
+ (regs->r0 == ti->syscall_saved_nr ||
+ regs->r0 == (unsigned long)-1)) {
+ regs->r0 = ENOSYS;
+ regs->r19 = 1;
}
- local_irq_disable();
- thread_flags = read_thread_flags();
- } while (thread_flags & _TIF_WORK_MASK);
+
+ instrumentation_end();
+
+ syscall_exit_to_user_mode(regs);
+ return;
+ }
+
+ /*
+ * Some successful syscalls, notably legacy ptrace PEEK requests,
+ * return arbitrary data in r0. That data may have the bit pattern
+ * of a negative errno, so do not infer failure from ret < 0 when
+ * arch code explicitly requested a successful Alpha return.
+ */
+ if (meta & ALPHA_SYSCALL_META_FORCE_SUCCESS) {
+ regs->r0 = ret;
+ regs->r19 = 0;
+ } else if (ret < 0) {
+ regs->r0 = -ret;
+ regs->r19 = 1;
+ } else {
+ regs->r0 = ret;
+ regs->r19 = 0;
+ }
+
+ instrumentation_end();
+ syscall_exit_to_user_mode(regs);
}
--
2.53.0
^ permalink raw reply related [flat|nested] 2+ messages in thread