Commit 6c9c7d8f authored by Michael Ellerman's avatar Michael Ellerman
Browse files

selftests/powerpc/ptrace: Add peek/poke of FPRs 



Currently the ptrace-gpr test only tests the GET/SET(FP)REGS ptrace
APIs. But there's an alternate (older) API, called PEEK/POKEUSR.

Add some minimal testing of PEEK/POKEUSR of the FPRs. This is sufficient
to detect the bug that was fixed recently in the 32-bit ptrace FPR
handling.

Depends-on: 8e127844 ("powerpc/32: Fix overread/overwrite of thread_struct via ptrace")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220627140239.2464900-13-mpe@ellerman.id.au
parent c5a814cc

tools/testing/selftests/powerpc/ptrace/ptrace-gpr.c

+22 −2
Original line number Diff line number Diff line
@@ -46,22 +46,42 @@ static int child(void) 


int trace_gpr(pid_t child)

{

	__u64 tmp, fpr[32], *peeked_fprs;

	unsigned long gpr[18];

	__u64 tmp, fpr[32];



	FAIL_IF(start_trace(child));



	// Check child GPRs match what we expect using GETREGS

	FAIL_IF(show_gpr(child, gpr));

	FAIL_IF(validate_gpr(gpr, child_gpr_val));

	FAIL_IF(show_fpr(child, fpr));



	// Check child FPRs match what we expect using GETFPREGS

	FAIL_IF(show_fpr(child, fpr));

	memcpy(&tmp, &child_fpr_val, sizeof(tmp));

	FAIL_IF(validate_fpr(fpr, tmp));



	// Check child FPRs match what we expect using PEEKUSR

	peeked_fprs = peek_fprs(child);

	FAIL_IF(!peeked_fprs);

	FAIL_IF(validate_fpr(peeked_fprs, tmp));

	free(peeked_fprs);



	// Write child GPRs using SETREGS

	FAIL_IF(write_gpr(child, parent_gpr_val));



	// Write child FPRs using SETFPREGS

	memcpy(&tmp, &parent_fpr_val, sizeof(tmp));

	FAIL_IF(write_fpr(child, tmp));



	// Check child FPRs match what we just set, using PEEKUSR

	peeked_fprs = peek_fprs(child);

	FAIL_IF(!peeked_fprs);

	FAIL_IF(validate_fpr(peeked_fprs, tmp));



	// Write child FPRs using POKEUSR

	FAIL_IF(poke_fprs(child, (unsigned long *)peeked_fprs));



	// Child will check its FPRs match before exiting

	FAIL_IF(stop_trace(child));



	return TEST_PASS;

tools/testing/selftests/powerpc/ptrace/ptrace.h

+65 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <sys/ipc.h>

#include <sys/shm.h>

#include <sys/user.h>

#include <sys/syscall.h>

#include <linux/elf.h>

#include <linux/types.h>

#include <linux/auxvec.h>
@@ -440,6 +441,70 @@ int show_gpr(pid_t child, unsigned long *gpr) 
	return TEST_PASS;

}



long sys_ptrace(enum __ptrace_request request, pid_t pid, unsigned long addr, unsigned long data)

{

	return syscall(__NR_ptrace, request, pid, (void *)addr, data);

}



// 33 because of FPSCR

#define PT_NUM_FPRS	(33 * (sizeof(__u64) / sizeof(unsigned long)))



__u64 *peek_fprs(pid_t child)

{

	unsigned long *fprs, *p, addr;

	long ret;

	int i;



	fprs = malloc(sizeof(unsigned long) * PT_NUM_FPRS);

	if (!fprs) {

		perror("malloc() failed");

		return NULL;

	}



	for (i = 0, p = fprs; i < PT_NUM_FPRS; i++, p++) {

		addr = sizeof(unsigned long) * (PT_FPR0 + i);

		ret = sys_ptrace(PTRACE_PEEKUSER, child, addr, (unsigned long)p);

		if (ret) {

			perror("ptrace(PTRACE_PEEKUSR) failed");

			return NULL;

		}

	}



	addr = sizeof(unsigned long) * (PT_FPR0 + i);

	ret = sys_ptrace(PTRACE_PEEKUSER, child, addr, (unsigned long)&addr);

	if (!ret) {

		printf("ptrace(PTRACE_PEEKUSR) succeeded unexpectedly!\n");

		return NULL;

	}



	return (__u64 *)fprs;

}



int poke_fprs(pid_t child, unsigned long *fprs)

{

	unsigned long *p, addr;

	long ret;

	int i;



	for (i = 0, p = fprs; i < PT_NUM_FPRS; i++, p++) {

		addr = sizeof(unsigned long) * (PT_FPR0 + i);

		ret = sys_ptrace(PTRACE_POKEUSER, child, addr, *p);

		if (ret) {

			perror("ptrace(PTRACE_POKEUSR) failed");

			return -1;

		}

	}



	addr = sizeof(unsigned long) * (PT_FPR0 + i);

	ret = sys_ptrace(PTRACE_POKEUSER, child, addr, addr);

	if (!ret) {

		printf("ptrace(PTRACE_POKEUSR) succeeded unexpectedly!\n");

		return -1;

	}



	return 0;

}



int write_gpr(pid_t child, unsigned long val)

{

	struct pt_regs *regs;