tile: support CONTEXT_TRACKING and thus NOHZ_FULL

Add the TIF_NOHZ flag appropriately.

Add call to user_exit() on entry to do_work_pending() and on entry
to syscalls via do_syscall_trace_enter(), and also the top of
do_syscall_trace_exit() just because it's done in x86.

Add call to user_enter() at the bottom of do_work_pending() once we
have no more work to do before returning to userspace.

Wrap all the trap code in exception_enter() / exception_exit().

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Chris Metcalf 2015-03-23 14:23:58 -04:00
parent b340c656af
commit 49e4e15619
8 changed files with 67 additions and 28 deletions

View File

@ -27,6 +27,7 @@ config TILE
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select HAVE_DEBUG_STACKOVERFLOW
select ARCH_WANT_FRAME_POINTERS
select HAVE_CONTEXT_TRACKING
# FIXME: investigate whether we need/want these options.
# select HAVE_IOREMAP_PROT

View File

@ -126,6 +126,7 @@ extern void _cpu_idle(void);
#define TIF_NOTIFY_RESUME 8 /* callback before returning to user */
#define TIF_SYSCALL_TRACEPOINT 9 /* syscall tracepoint instrumentation */
#define TIF_POLLING_NRFLAG 10 /* idle is polling for TIF_NEED_RESCHED */
#define TIF_NOHZ 11 /* in adaptive nohz mode */
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
@ -138,14 +139,16 @@ extern void _cpu_idle(void);
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_NOHZ (1<<TIF_NOHZ)
/* Work to do on any return to user space. */
#define _TIF_ALLWORK_MASK \
(_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SINGLESTEP|\
_TIF_ASYNC_TLB|_TIF_NOTIFY_RESUME)
(_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_SINGLESTEP | \
_TIF_ASYNC_TLB | _TIF_NOTIFY_RESUME | _TIF_NOHZ)
/* Work to do at syscall entry. */
#define _TIF_SYSCALL_ENTRY_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)
#define _TIF_SYSCALL_ENTRY_WORK \
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)
/* Work to do at syscall exit. */
#define _TIF_SYSCALL_EXIT_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)

View File

@ -27,6 +27,7 @@
#include <linux/kernel.h>
#include <linux/tracehook.h>
#include <linux/signal.h>
#include <linux/context_tracking.h>
#include <asm/stack.h>
#include <asm/switch_to.h>
#include <asm/homecache.h>
@ -474,6 +475,8 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
if (!user_mode(regs))
return 0;
user_exit();
/* Enable interrupts; they are disabled again on return to caller. */
local_irq_enable();
@ -496,11 +499,12 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
tracehook_notify_resume(regs);
return 1;
}
if (thread_info_flags & _TIF_SINGLESTEP) {
if (thread_info_flags & _TIF_SINGLESTEP)
single_step_once(regs);
return 0;
}
panic("work_pending: bad flags %#x\n", thread_info_flags);
user_enter();
return 0;
}
unsigned long get_wchan(struct task_struct *p)

View File

@ -22,6 +22,7 @@
#include <linux/regset.h>
#include <linux/elf.h>
#include <linux/tracehook.h>
#include <linux/context_tracking.h>
#include <asm/traps.h>
#include <arch/chip.h>
@ -252,12 +253,21 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
int do_syscall_trace_enter(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACE)) {
u32 work = ACCESS_ONCE(current_thread_info()->flags);
/*
* If TIF_NOHZ is set, we are required to call user_exit() before
* doing anything that could touch RCU.
*/
if (work & _TIF_NOHZ)
user_exit();
if (work & _TIF_SYSCALL_TRACE) {
if (tracehook_report_syscall_entry(regs))
regs->regs[TREG_SYSCALL_NR] = -1;
}
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
if (work & _TIF_SYSCALL_TRACEPOINT)
trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);
return regs->regs[TREG_SYSCALL_NR];
@ -267,6 +277,12 @@ void do_syscall_trace_exit(struct pt_regs *regs)
{
long errno;
/*
* We may come here right after calling schedule_user()
* in which case we can be in RCU user mode.
*/
user_exit();
/*
* The standard tile calling convention returns the value (or negative
* errno) in r0, and zero (or positive errno) in r1.
@ -303,5 +319,7 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs)
/* Handle synthetic interrupt delivered only by the simulator. */
void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
{
enum ctx_state prev_state = exception_enter();
send_sigtrap(current, regs);
exception_exit(prev_state);
}

View File

@ -23,6 +23,7 @@
#include <linux/types.h>
#include <linux/err.h>
#include <linux/prctl.h>
#include <linux/context_tracking.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
@ -738,6 +739,7 @@ static DEFINE_PER_CPU(unsigned long, ss_saved_pc);
void gx_singlestep_handle(struct pt_regs *regs, int fault_num)
{
enum ctx_state prev_state = exception_enter();
unsigned long *ss_pc = this_cpu_ptr(&ss_saved_pc);
struct thread_info *info = (void *)current_thread_info();
int is_single_step = test_ti_thread_flag(info, TIF_SINGLESTEP);
@ -754,6 +756,7 @@ void gx_singlestep_handle(struct pt_regs *regs, int fault_num)
__insn_mtspr(SPR_SINGLE_STEP_CONTROL_K, control);
send_sigtrap(current, regs);
}
exception_exit(prev_state);
}

View File

@ -20,6 +20,7 @@
#include <linux/reboot.h>
#include <linux/uaccess.h>
#include <linux/ptrace.h>
#include <linux/context_tracking.h>
#include <asm/stack.h>
#include <asm/traps.h>
#include <asm/setup.h>
@ -253,6 +254,7 @@ static int do_bpt(struct pt_regs *regs)
void __kprobes do_trap(struct pt_regs *regs, int fault_num,
unsigned long reason)
{
enum ctx_state prev_state = exception_enter();
siginfo_t info = { 0 };
int signo, code;
unsigned long address = 0;
@ -261,7 +263,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
/* Handle breakpoints, etc. */
if (is_kernel && fault_num == INT_ILL && do_bpt(regs))
return;
goto done;
/* Re-enable interrupts, if they were previously enabled. */
if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
@ -275,7 +277,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
const char *name;
char buf[100];
if (fixup_exception(regs)) /* ILL_TRANS or UNALIGN_DATA */
return;
goto done;
if (fault_num >= 0 &&
fault_num < ARRAY_SIZE(int_name) &&
int_name[fault_num] != NULL)
@ -294,7 +296,6 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
fault_num, name, regs->pc, buf);
show_regs(regs);
do_exit(SIGKILL); /* FIXME: implement i386 die() */
return;
}
switch (fault_num) {
@ -308,7 +309,6 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
pr_err("Unreadable instruction for INT_ILL: %#lx\n",
regs->pc);
do_exit(SIGKILL);
return;
}
if (!special_ill(instr, &signo, &code)) {
signo = SIGILL;
@ -319,7 +319,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
case INT_GPV:
#if CHIP_HAS_TILE_DMA()
if (retry_gpv(reason))
return;
goto done;
#endif
/*FALLTHROUGH*/
case INT_UDN_ACCESS:
@ -346,7 +346,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
if (!state ||
(void __user *)(regs->pc) != state->buffer) {
single_step_once(regs);
return;
goto done;
}
}
#endif
@ -380,7 +380,6 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
#endif
default:
panic("Unexpected do_trap interrupt number %d", fault_num);
return;
}
info.si_signo = signo;
@ -391,6 +390,9 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
if (signo != SIGTRAP)
trace_unhandled_signal("trap", regs, address, signo);
force_sig_info(signo, &info, current);
done:
exception_exit(prev_state);
}
void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)

View File

@ -25,6 +25,7 @@
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/prctl.h>
#include <linux/context_tracking.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
@ -1448,6 +1449,7 @@ void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
void do_unaligned(struct pt_regs *regs, int vecnum)
{
enum ctx_state prev_state = exception_enter();
tilegx_bundle_bits __user *pc;
tilegx_bundle_bits bundle;
struct thread_info *info = current_thread_info();
@ -1487,12 +1489,11 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
(int)unaligned_fixup,
(unsigned long long)regs->ex1,
(unsigned long long)regs->pc);
return;
} else {
/* Not fixable. Go panic. */
panic("Unalign exception in Kernel. pc=%lx",
regs->pc);
}
/* Not fixable. Go panic. */
panic("Unalign exception in Kernel. pc=%lx",
regs->pc);
return;
} else {
/*
* Try to fix the exception. If we can't, panic the
@ -1501,8 +1502,8 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
bundle = GX_INSN_BSWAP(
*((tilegx_bundle_bits *)(regs->pc)));
jit_bundle_gen(regs, bundle, align_ctl);
return;
}
goto done;
}
/*
@ -1526,7 +1527,7 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
trace_unhandled_signal("unaligned fixup trap", regs, 0, SIGBUS);
force_sig_info(info.si_signo, &info, current);
return;
goto done;
}
@ -1543,7 +1544,7 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
trace_unhandled_signal("segfault in unalign fixup", regs,
(unsigned long)info.si_addr, SIGSEGV);
force_sig_info(info.si_signo, &info, current);
return;
goto done;
}
if (!info->unalign_jit_base) {
@ -1578,7 +1579,7 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
if (IS_ERR((void __force *)user_page)) {
pr_err("Out of kernel pages trying do_mmap\n");
return;
goto done;
}
/* Save the address in the thread_info struct */
@ -1591,6 +1592,9 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
/* Generate unalign JIT */
jit_bundle_gen(regs, GX_INSN_BSWAP(bundle), align_ctl);
done:
exception_exit(prev_state);
}
#endif /* __tilegx__ */

View File

@ -35,6 +35,7 @@
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/kdebug.h>
#include <linux/context_tracking.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
@ -702,6 +703,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
unsigned long address, unsigned long write)
{
int is_page_fault;
enum ctx_state prev_state = exception_enter();
#ifdef CONFIG_KPROBES
/*
@ -711,7 +713,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
*/
if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
regs->faultnum, SIGSEGV) == NOTIFY_STOP)
return;
goto done;
#endif
#ifdef __tilegx__
@ -750,7 +752,6 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
current->comm, current->pid, pc, address);
show_regs(regs);
do_group_exit(SIGKILL);
return;
}
}
#else
@ -834,12 +835,15 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
async->is_fault = is_page_fault;
async->is_write = write;
async->address = address;
return;
goto done;
}
}
#endif
handle_page_fault(regs, fault_num, is_page_fault, address, write);
done:
exception_exit(prev_state);
}