selftests/powerpc: Add checks for transactional GPRs in signal contexts

If a thread receives a signal while transactional the kernel creates a
second context to show the transactional state of the process. This
test loads some known values and waits for a signal and confirms that
the expected values are in the signal context.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Cyril Bur 2016-09-23 16:18:20 +10:00 committed by Michael Ellerman
parent ef186331b4
commit f10d4424b2
3 changed files with 210 additions and 1 deletions

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@ -1,5 +1,7 @@
SIGNAL_CONTEXT_CHK_TESTS := tm-signal-context-chk-gpr
TEST_PROGS := tm-resched-dscr tm-syscall tm-signal-msr-resv tm-signal-stack \
tm-vmxcopy tm-fork tm-tar tm-tmspr tm-exec tm-execed
tm-vmxcopy tm-fork tm-tar tm-tmspr $(SIGNAL_CONTEXT_CHK_TESTS)
all: $(TEST_PROGS)
@ -11,6 +13,9 @@ tm-syscall: tm-syscall-asm.S
tm-syscall: CFLAGS += -I../../../../../usr/include
tm-tmspr: CFLAGS += -pthread
$(SIGNAL_CONTEXT_CHK_TESTS): tm-signal.S
$(SIGNAL_CONTEXT_CHK_TESTS): CFLAGS += -mhtm -m64 -mvsx
include ../../lib.mk
clean:

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@ -0,0 +1,90 @@
/*
* Copyright 2016, Cyril Bur, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*
* Test the kernel's signal frame code.
*
* The kernel sets up two sets of ucontexts if the signal was to be
* delivered while the thread was in a transaction.
* Expected behaviour is that the checkpointed state is in the user
* context passed to the signal handler. The speculated state can be
* accessed with the uc_link pointer.
*
* The rationale for this is that if TM unaware code (which linked
* against TM libs) installs a signal handler it will not know of the
* speculative nature of the 'live' registers and may infer the wrong
* thing.
*/
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <altivec.h>
#include "utils.h"
#include "tm.h"
#define MAX_ATTEMPT 500000
#define NV_GPR_REGS 18
long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
static sig_atomic_t fail;
static long gps[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
-1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18};
static void signal_usr1(int signum, siginfo_t *info, void *uc)
{
int i;
ucontext_t *ucp = uc;
ucontext_t *tm_ucp = ucp->uc_link;
for (i = 0; i < NV_GPR_REGS && !fail; i++) {
fail = (ucp->uc_mcontext.gp_regs[i + 14] != gps[i]);
fail |= (tm_ucp->uc_mcontext.gp_regs[i + 14] != gps[i + NV_GPR_REGS]);
if (fail)
printf("Failed on %d GPR %lu or %lu\n", i,
ucp->uc_mcontext.gp_regs[i + 14], tm_ucp->uc_mcontext.gp_regs[i + 14]);
}
}
static int tm_signal_context_chk_gpr()
{
struct sigaction act;
int i;
long rc;
pid_t pid = getpid();
SKIP_IF(!have_htm());
act.sa_sigaction = signal_usr1;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
if (sigaction(SIGUSR1, &act, NULL) < 0) {
perror("sigaction sigusr1");
exit(1);
}
i = 0;
while (i < MAX_ATTEMPT && !fail) {
rc = tm_signal_self_context_load(pid, gps, NULL, NULL, NULL);
FAIL_IF(rc != pid);
i++;
}
return fail;
}
int main(void)
{
return test_harness(tm_signal_context_chk_gpr, "tm_signal_context_chk_gpr");
}

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@ -0,0 +1,114 @@
/*
* Copyright 2015, Cyril Bur, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include "../basic_asm.h"
#include "../gpr_asm.h"
#include "../fpu_asm.h"
#include "../vmx_asm.h"
#include "../vsx_asm.h"
/*
* Large caveat here being that the caller cannot expect the
* signal to always be sent! The hardware can (AND WILL!) abort
* the transaction between the tbegin and the tsuspend (however
* unlikely it seems or infrequently it actually happens).
* You have been warned.
*/
/* long tm_signal_self(pid_t pid, long *gprs, double *fps, vector *vms, vector *vss); */
FUNC_START(tm_signal_self_context_load)
PUSH_BASIC_STACK(512)
/*
* Don't strictly need to save and restore as it depends on if
* we're going to use them, however this reduces messy logic
*/
PUSH_VMX(STACK_FRAME_LOCAL(5,0),r8)
PUSH_FPU(512)
PUSH_NVREGS_BELOW_FPU(512)
std r3, STACK_FRAME_PARAM(0)(sp) /* pid */
std r4, STACK_FRAME_PARAM(1)(sp) /* gps */
std r5, STACK_FRAME_PARAM(2)(sp) /* fps */
std r6, STACK_FRAME_PARAM(3)(sp) /* vms */
std r7, STACK_FRAME_PARAM(4)(sp) /* vss */
ld r3, STACK_FRAME_PARAM(1)(sp)
cmpdi r3, 0
beq skip_gpr_lc
bl load_gpr
skip_gpr_lc:
ld r3, STACK_FRAME_PARAM(2)(sp)
cmpdi r3, 0
beq skip_fpu_lc
bl load_fpu
skip_fpu_lc:
ld r3, STACK_FRAME_PARAM(3)(sp)
cmpdi r3, 0
beq skip_vmx_lc
bl load_vmx
skip_vmx_lc:
ld r3, STACK_FRAME_PARAM(4)(sp)
cmpdi r3, 0
beq skip_vsx_lc
bl load_vsx
skip_vsx_lc:
/*
* Set r3 (return value) before tbegin. Use the pid as a known
* 'all good' return value, zero is used to indicate a non-doomed
* transaction.
*/
ld r3, STACK_FRAME_PARAM(0)(sp)
tbegin.
beq 1f
tsuspend. /* Can't enter a syscall transactionally */
ld r3, STACK_FRAME_PARAM(1)(sp)
cmpdi r3, 0
beq skip_gpr_lt
/* Get the second half of the array */
addi r3, r3, 8 * 18
bl load_gpr
skip_gpr_lt:
ld r3, STACK_FRAME_PARAM(2)(sp)
cmpdi r3, 0
beq skip_fpu_lt
/* Get the second half of the array */
addi r3, r3, 8 * 18
bl load_fpu
skip_fpu_lt:
ld r3, STACK_FRAME_PARAM(3)(sp)
cmpdi r3, 0
beq skip_vmx_lt
/* Get the second half of the array */
addi r3, r3, 16 * 12
bl load_vmx
skip_vmx_lt:
ld r3, STACK_FRAME_PARAM(4)(sp)
cmpdi r3, 0
beq skip_vsx_lt
/* Get the second half of the array */
addi r3, r3, 16 * 12
bl load_vsx
skip_vsx_lt:
li r0, 37 /* sys_kill */
ld r3, STACK_FRAME_PARAM(0)(sp) /* pid */
li r4, 10 /* SIGUSR1 */
sc /* Taking the signal will doom the transaction */
tabort. 0
tresume. /* Be super sure we abort */
/*
* This will cause us to resume doomed transaction and cause
* hardware to cleanup, we'll end up at 1: anything between
* tresume. and 1: shouldn't ever run.
*/
li r3, 0
1:
POP_VMX(STACK_FRAME_LOCAL(5,0),r4)
POP_FPU(512)
POP_NVREGS_BELOW_FPU(512)
POP_BASIC_STACK(512)
blr
FUNC_END(tm_signal_self_context_load)