[PATCH V2 0/3] Add new PowerPC specific ELF core notes

From: Anshuman Khandual
Date: Mon May 05 2014 - 03:56:37 EST

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This patch series adds five new ELF core note sections which can be
used with existing ptrace request PTRACE_GETREGSET/SETREGSET for accessing
various transactional memory and miscellaneous register sets on PowerPC
platform. Please find a test program exploiting these new ELF core note
types on a POWER8 system.

RFC: https://lkml.org/lkml/2014/4/1/292
V1: https://lkml.org/lkml/2014/4/2/43

Changes in V2
=============
(1) Removed all the power specific ptrace requests corresponding to new NT_PPC_*
elf core note types. Now all the register sets can be accessed from ptrace
through PTRACE_GETREGSET/PTRACE_SETREGSET using the individual NT_PPC* core
note type instead
(2) Fixed couple of attribute values for REGSET_TM_CGPR register set
(3) Renamed flush_tmreg_to_thread as flush_tmregs_to_thread
(4) Fixed 32 bit checkpointed GPR support
(5) Changed commit messages accordingly

Outstanding Issues
==================
(1) Running DSCR register value inside a transaction does not seem to be saved
at thread.dscr when the process stops for ptrace examination.

Test programs
=============
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <errno.h>
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/user.h>
#include <linux/elf.h>
#include <linux/types.h>
#include <linux/ptrace.h>

typedef long long u64;
typedef unsigned int u32;
typedef __vector128 vector128;

/* TM CFPR */
struct tm_cfpr {
u64 fpr[32];
u64 fpscr;
};

/* TM CVMX */
struct tm_cvmx {
vector128 vr[32] __attribute__((aligned(16)));
vector128 vscr __attribute__((aligned(16)));
u32 vrsave;
};

/* TM SPR */
struct tm_spr_regs {
u64 tm_tfhar;
u64 tm_texasr;
u64 tm_tfiar;
u64 tm_orig_msr;
u64 tm_tar;
u64 tm_ppr;
u64 tm_dscr;
};

/* Miscellaneous registers */
struct misc_regs {
u64 dscr;
u64 ppr;
u64 tar;
};

/* TM instructions */
#define TBEGIN ".long 0x7C00051D ;"
#define TEND ".long 0x7C00055D ;"

/* SPR number */
#define SPRN_DSCR 0x3
#define SPRN_TAR 815

/* ELF core notes */
#define NT_PPC_TM_SPR 0x103 /* PowerPC transactional memory special registers */
#define NT_PPC_TM_CGPR 0x104 /* PowerpC transactional memory checkpointed GPR */
#define NT_PPC_TM_CFPR 0x105 /* PowerPC transactional memory checkpointed FPR */
#define NT_PPC_TM_CVMX 0x106 /* PowerPC transactional memory checkpointed VMX */
#define NT_PPC_MISC 0x107 /* PowerPC miscellaneous registers */

#define VAL1 1
#define VAL2 2
#define VAL3 3
#define VAL4 4

int main(int argc, char *argv[])
{
struct tm_spr_regs *tmr1;
struct pt_regs *pregs1, *pregs2;
struct tm_cfpr *fpr, *fpr1;
struct misc_regs *dbr1;
struct iovec iov;

pid_t child;
int ret = 0, status = 0, i = 0, flag = 1;

pregs2 = (struct pt_regs *) malloc(sizeof(struct pt_regs));
fpr = (struct tm_cfpr *) malloc(sizeof(struct tm_cfpr));

child = fork();
if (child < 0) {
printf("fork() failed \n");
exit(-1);
}

/* Child code */
if (child == 0) {
asm __volatile__(
"6: ;" /* TM checkpointed values */
"li 1, %[val1];" /* GPR[1] */
".long 0x7C210166;" /* FPR[1] */
"li 2, %[val2];" /* GPR[2] */
".long 0x7C420166;" /* FPR[2] */
"mtspr %[tar], 1;" /* TAR */
"mtspr %[dscr], 2;" /* DSCR */
"1: ;"
TBEGIN /* TM running values */
"beq 2f ;"
"li 1, %[val3];" /* GPR[1] */
".long 0x7C210166;" /* FPR[1] */
"li 2, %[val4];" /* GPR[2] */
".long 0x7C420166;" /* FPR[2] */
"mtspr %[tar], 1;" /* TAR */
"mtspr %[dscr], 2;" /* DSCR */
"b .;"
TEND
"2: ;" /* Abort handler */
"b 1b;" /* Start from TBEGIN */

"3: ;"
"b 6b;" /* Start all over again */
:: [dscr]"i"(SPRN_DSCR), [tar]"i"(SPRN_TAR), [val1]"i"(VAL1), [val2]"i"(VAL2), [val3]"i"(VAL3), [val4]"i"(VAL4)
: "memory", "r7");
}

/* Parent */
if (child) {
do {
memset(pregs2, 0 , sizeof(struct pt_regs));
memset(fpr, 0 , sizeof(struct tm_cfpr));

/* Wait till child hits "b ." instruction */
sleep(3);

/* Attach tracee */
ret = ptrace(PTRACE_ATTACH, child, NULL, NULL);
if (ret == -1) {
printf("PTRACE_ATTACH failed: %s\n", strerror(errno));
exit(-1);
}

ret = waitpid(child, NULL, 0);
if (ret != child) {
printf("PID does not match\n");
exit(-1);
}

/* TM specific SPR */
iov.iov_base = (struct tm_spr_regs *) malloc(sizeof(struct tm_spr_regs));
iov.iov_len = sizeof(struct tm_spr_regs);
ret = ptrace(PTRACE_GETREGSET, child, NT_PPC_TM_SPR, &iov);
if (ret == -1) {
printf("PTRACE_GETREGSET: NT_PPC_TM_SPR failed %s\n", strerror(errno));
exit(-1);
}

if (iov.iov_len != sizeof(struct tm_spr_regs)) {
printf("NT_PPC_TM_SPR: Length returned is wrong\n");
exit(-1);
}

tmr1 = iov.iov_base;
printf("-------TM specific SPR------\n");
printf("TM TFHAR: %llx\n", tmr1->tm_tfhar);
printf("TM TEXASR: %llx\n", tmr1->tm_texasr);
printf("TM TFIAR: %llx\n", tmr1->tm_tfiar);
printf("TM CH ORIG_MSR: %llx\n", tmr1->tm_orig_msr);
printf("TM CH TAR: %llx\n", tmr1->tm_tar);
printf("TM CH PPR: %llx\n", tmr1->tm_ppr);
printf("TM CH DSCR: %llx\n", tmr1->tm_dscr);

if (tmr1->tm_tar == VAL1)
printf("TAR PASSED\n");
else
printf("TAR FAILED\n");

if (tmr1->tm_dscr == VAL2)
printf("DSCR PASSED\n");
else
printf("DSCR FAILED\n");

/* TM checkpointed GPR */
iov.iov_base = (struct pt_regs *) malloc(sizeof(struct pt_regs));;
iov.iov_len = sizeof(struct pt_regs);
ret = ptrace(PTRACE_GETREGSET, child, NT_PPC_TM_CGPR, &iov);
if (ret == -1) {
printf("PTRACE_GETREGSET: NT_PPC_TM_CGPR failed: %s\n", strerror(errno));
exit(-1);
}

if (iov.iov_len != sizeof(struct pt_regs)) {
printf("NT_PPC_TM_CGPR: Length returned is wrong\n");
exit(-1);
}

pregs1 = iov.iov_base;
printf("-------TM checkpointed GPR-----\n");
printf("TM CH GPR[1]: %x\n", pregs1->gpr[1]);
printf("TM CH GPR[2]: %x\n", pregs1->gpr[2]);
printf("TM CH NIP: %x\n", pregs1->nip);
printf("TM CH LINK: %x\n", pregs1->link);
printf("TM CH CCR: %x\n", pregs1->ccr);

if (pregs1->gpr[1] == VAL1)
printf("GPR[1] PASSED\n");
else
printf("GPR[1] FAILED\n");

if (pregs1->gpr[2] == VAL2)
printf("GPR[2] PASSED\n");
else
printf("GPR[2] FAILED\n");

/* TM running GPR */
ret = ptrace(PTRACE_GETREGS, child, NULL, pregs2);
if (ret == -1) {
printf("PTRACE_GETREGS fail: %s\n", strerror(errno));
exit(-1);
}

printf("-------TM running GPR-----\n");
printf("TM RN GPR[1]: %x\n", pregs2->gpr[1]);
printf("TM RN GPR[2]: %x\n", pregs2->gpr[2]);
printf("TM RN NIP: %x\n", pregs2->nip);
printf("TM RN LINK: %x\n", pregs2->link);
printf("TM RN CCR: %x\n", pregs2->ccr);

if (pregs2->gpr[1] == VAL3)
printf("GPR[1] PASSED\n");
else
printf("GPR[1] FAILED\n");

if (pregs2->gpr[2] == VAL4)
printf("GPR[2] PASSED\n");
else
printf("GPR[2] FAILED\n");

/* TM checkpointed FPR */
iov.iov_base = (struct tm_cfpr *) malloc(sizeof(struct tm_cfpr));;
iov.iov_len = sizeof(struct tm_cfpr);
ret = ptrace(PTRACE_GETREGSET, child, NT_PPC_TM_CFPR, &iov);
if (ret == -1) {
printf("PTRACE_GETREGSET: NT_PPC_TM_CFPR: Failed: %s\n", strerror(errno));
exit(-1);
}

if (iov.iov_len != sizeof(struct tm_cfpr)) {
printf("NT_PPC_TM_CFPR: Length returned is wrong\n");
exit(-1);
}

fpr1 = iov.iov_base;
printf("-------TM checkpointed FPR-----\n");
printf("TM CH FPR[1]: %llx\n", fpr1->fpr[1]);
printf("TM CH FPR[2]: %llx\n", fpr1->fpr[2]);
printf("TM CH FPSCR: %llx\n", fpr1->fpscr);

if (fpr1->fpr[1] == VAL1)
printf("FPR[1] PASSED\n");
else
printf("FPR[1] FAILED\n");

if (fpr1->fpr[2] == VAL2)
printf("FPR[2] PASSED\n");
else
printf("FPR[2] FAILED\n");

/* TM running FPR */
ret = ptrace(PTRACE_GETFPREGS, child, NULL, fpr);
if (ret == -1) {
printf("PTRACE_GETFPREGS failed: %s\n", strerror(errno));
exit(-1);
}

printf("-------TM running FPR-----\n");
printf("TM RN FPR[1]: %llx\n", fpr->fpr[1]);
printf("TM RN FPR[2]: %llx\n", fpr->fpr[2]);
printf("TM RN FPSCR: %llx\n", fpr->fpscr);

if (fpr->fpr[1] == VAL3)
printf("FPR[1] PASSED\n");
else
printf("FPR[1] FAILED\n");

if (fpr->fpr[2] == VAL4)
printf("FPR[2] PASSED\n");
else
printf("FPR[2] FAILED\n");

/* Misc registers */
iov.iov_base = (struct misc_regs *) malloc(sizeof(struct misc_regs));
iov.iov_len = sizeof(struct misc_regs);
ret = ptrace(PTRACE_GETREGSET, child, NT_PPC_MISC, &iov);
if (ret == -1) {
printf("PTRACE_GETREGSET: NT_PPC_MISC: Failed: %s\n", strerror(errno));
exit(-1);
}

if (iov.iov_len != sizeof(struct misc_regs)) {
printf("NT_PPC_TM_MISC: Length returned is wrong\n");
exit(-1);
}

dbr1 = iov.iov_base;
printf("-------Running miscellaneous registers-------\n");
printf("TM RN DSCR: %llx\n", dbr1->dscr);
printf("TM RN PPR: %llx\n", dbr1->ppr);
printf("TM RN TAR: %llx\n", dbr1->tar);

if (dbr1->tar == VAL3)
printf("TAR PASSED\n");
else
printf("TAR FAILED\n");

if (dbr1->dscr == VAL4)
printf("DSCR PASSED\n");
else
printf("DSCR FAILED\n");

/* Detach tracee */
ret = ptrace(PTRACE_DETACH, child, NULL, NULL);
if (ret == -1) {
printf("PTRACE_DETACH failed: %s\n", strerror(errno));
exit(-1);
}
} while (0);
}
return 0;
}

Test Results
============
(1) 64 bit application ==>

-------TM specific SPR------
TM TFHAR: 10000960
TM TEXASR: de000001ac000001
TM TFIAR: c00000000003f9a6
TM CH ORIG_MSR: 900000050000f032
TM CH TAR: 1
TM CH PPR: c000000000000
TM CH DSCR: 2
TAR PASSED
DSCR PASSED
-------TM checkpointed GPR-----
TM CH GPR[1]: 1
TM CH GPR[2]: 2
TM CH NIP: 10000960
TM CH LINK: 10000904
TM CH CCR: 22000022
GPR[1] PASSED
GPR[2] PASSED
-------TM running GPR-----
TM RN GPR[1]: 3
TM RN GPR[2]: 4
TM RN NIP: 1000097c
TM RN LINK: 10000904
TM RN CCR: 2000022
GPR[1] PASSED
GPR[2] PASSED
-------TM checkpointed FPR-----
TM CH FPR[1]: 1
TM CH FPR[2]: 2
TM CH FPSCR: 0
FPR[1] PASSED
FPR[2] PASSED
-------TM running FPR-----
TM RN FPR[1]: 3
TM RN FPR[2]: 4
TM RN FPSCR: 0
FPR[1] PASSED
FPR[2] PASSED
-------Running miscellaneous registers-------
TM RN DSCR: 0
TM RN PPR: c000000000000
TM RN TAR: 3
TAR PASSED
DSCR FAILED

(2) 32 bit application ==>

-------TM specific SPR------
TM TFHAR: 100006b8
TM TEXASR: de000001ac000001
TM TFIAR: c00000000003f9a6
TM CH ORIG_MSR: 100000050000f032
TM CH TAR: 1
TM CH PPR: c000000000000
TM CH DSCR: 2
TAR PASSED
DSCR PASSED
-------TM checkpointed GPR-----
TM CH GPR[1]: 1
TM CH GPR[2]: 2
TM CH NIP: 100006b8
TM CH LINK: 1000066c
TM CH CCR: 22000022
GPR[1] PASSED
GPR[2] PASSED
-------TM running GPR-----
TM RN GPR[1]: 3
TM RN GPR[2]: 4
TM RN NIP: 100006d4
TM RN LINK: 1000066c
TM RN CCR: 2000022
GPR[1] PASSED
GPR[2] PASSED
TM CH FPR[2]: 2
TM CH FPSCR: 0
FPR[1] PASSED
FPR[2] PASSED
-------TM running FPR-----
TM RN FPR[1]: 3
TM RN FPR[2]: 4
TM RN FPSCR: 0
FPR[1] PASSED
FPR[2] PASSED
-------Running miscellaneous registers-------
TM RN DSCR: 0
TM RN PPR: c000000000000
TM RN TAR: 3
TAR PASSED
DSCR FAILED

Anshuman Khandual (3):
elf: Add some new PowerPC specifc note sections
powerpc, ptrace: Enable support for transactional memory register sets
powerpc, ptrace: Enable support for miscellaneous registers

arch/powerpc/include/asm/switch_to.h | 8 +
arch/powerpc/kernel/process.c | 24 ++
arch/powerpc/kernel/ptrace.c | 764 +++++++++++++++++++++++++++++++++--
include/uapi/linux/elf.h | 5 +
4 files changed, 773 insertions(+), 28 deletions(-)

--
1.7.11.7

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Next message: Anshuman Khandual: "[PATCH V2 3/3] powerpc, ptrace: Enable support for miscellaneous registers"
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