All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michael Ellerman <mpe@ellerman.id.au>
To: <linuxppc-dev@lists.ozlabs.org>
Subject: [PATCH 10/13] selftests/powerpc/ptrace: Do more of ptrace-gpr in asm
Date: Tue, 28 Jun 2022 00:02:36 +1000	[thread overview]
Message-ID: <20220627140239.2464900-10-mpe@ellerman.id.au> (raw)
In-Reply-To: <20220627140239.2464900-1-mpe@ellerman.id.au>

The ptrace-gpr test includes some inline asm to load GPR and FPR
registers. It then goes back to C to wait for the parent to trace it and
then checks register contents.

The split between inline asm and C is fragile, it relies on the compiler
not using any non-volatile GPRs after the inline asm block. It also
requires a very large and unwieldy inline asm block.

So convert the logic to set registers, wait, and store registers to a
single asm function, meaning there's no window for the compiler to
intervene.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 .../selftests/powerpc/include/basic_asm.h     |  8 +++
 .../testing/selftests/powerpc/ptrace/Makefile |  1 +
 .../selftests/powerpc/ptrace/ptrace-gpr.S     | 52 +++++++++++++++++++
 .../selftests/powerpc/ptrace/ptrace-gpr.c     | 29 +++++------
 4 files changed, 73 insertions(+), 17 deletions(-)
 create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-gpr.S

diff --git a/tools/testing/selftests/powerpc/include/basic_asm.h b/tools/testing/selftests/powerpc/include/basic_asm.h
index 2d7f6e592dd9..26cde8ea1f49 100644
--- a/tools/testing/selftests/powerpc/include/basic_asm.h
+++ b/tools/testing/selftests/powerpc/include/basic_asm.h
@@ -94,4 +94,12 @@
 	PPC_LL	r0, STACK_FRAME_LR_POS(%r1); \
 	mtlr	r0;
 
+.macro OP_REGS op, reg_width, start_reg, end_reg, base_reg, base_reg_offset=0, skip=0
+	.set i, \start_reg
+	.rept (\end_reg - \start_reg + 1)
+	\op	i, (\reg_width * (i - \skip) + \base_reg_offset)(\base_reg)
+	.set i, i + 1
+	.endr
+.endm
+
 #endif /* _SELFTESTS_POWERPC_BASIC_ASM_H */
diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile
index 3434a624ed77..2f02cb54224d 100644
--- a/tools/testing/selftests/powerpc/ptrace/Makefile
+++ b/tools/testing/selftests/powerpc/ptrace/Makefile
@@ -35,6 +35,7 @@ $(TM_TESTS): CFLAGS += -I../tm -mhtm
 
 CFLAGS += -I../../../../../usr/include -fno-pie
 
+$(OUTPUT)/ptrace-gpr: ptrace-gpr.S
 $(OUTPUT)/ptrace-pkey $(OUTPUT)/core-pkey: LDLIBS += -pthread
 
 $(TEST_GEN_PROGS): ../harness.c ../utils.c ../lib/reg.S
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.S b/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.S
new file mode 100644
index 000000000000..070e8443e3cc
--- /dev/null
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.S
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * test helper assembly functions
+ *
+ * Copyright (C) 2016 Simon Guo, IBM Corporation.
+ * Copyright 2022 Michael Ellerman, IBM Corporation.
+ */
+#include "basic_asm.h"
+
+#define GPR_SIZE	__SIZEOF_LONG__
+#define FIRST_GPR	14
+#define NUM_GPRS	(32 - FIRST_GPR)
+#define STACK_SIZE	(NUM_GPRS * GPR_SIZE)
+
+// gpr_child_loop(int *read_flag, int *write_flag,
+//		  unsigned long *gpr_buf, double *fpr_buf);
+FUNC_START(gpr_child_loop)
+	// r3 = read_flag
+	// r4 = write_flag
+	// r5 = gpr_buf
+	// r6 = fpr_buf
+	PUSH_BASIC_STACK(STACK_SIZE)
+
+	// Save non-volatile GPRs
+	OP_REGS PPC_STL, GPR_SIZE, FIRST_GPR, 31, %r1, STACK_FRAME_LOCAL(0, 0), FIRST_GPR
+
+	// Load GPRs with expected values
+	OP_REGS PPC_LL, GPR_SIZE, FIRST_GPR, 31, r5, 0, FIRST_GPR
+
+	// Load FPRs with expected values
+	OP_REGS lfd, 8, 0, 31, r6
+
+	// Signal to parent that we're ready
+	li	r0, 1
+	stw	r0, 0(r4)
+
+	// Wait for parent to finish
+1:	lwz	r0, 0(r3)
+	cmpwi	r0, 0
+	beq	1b	// Loop while flag is zero
+
+	// Save GPRs back to caller buffer
+	OP_REGS PPC_STL, GPR_SIZE, FIRST_GPR, 31, r5, 0, FIRST_GPR
+
+	// Save FPRs
+	OP_REGS stfd, 8, 0, 31, r6
+
+	// Reload non-volatile GPRs
+	OP_REGS PPC_LL, GPR_SIZE, FIRST_GPR, 31, %r1, STACK_FRAME_LOCAL(0, 0), FIRST_GPR
+
+	POP_BASIC_STACK(STACK_SIZE)
+	blr
diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.c b/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.c
index 1468e89c044b..4e7a7eb01e3a 100644
--- a/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.c
+++ b/tools/testing/selftests/powerpc/ptrace/ptrace-gpr.c
@@ -16,32 +16,27 @@ double a = FPR_1;
 double b = FPR_2;
 double c = FPR_3;
 
+extern void gpr_child_loop(int *read_flag, int *write_flag,
+			   unsigned long *gpr_buf, double *fpr_buf);
+
 void gpr(void)
 {
-	unsigned long gpr_buf[18];
+	unsigned long gpr_buf[32];
 	double fpr_buf[32];
+	int i;
 
 	cptr = (int *)shmat(shm_id, NULL, 0);
+	memset(gpr_buf, 0, sizeof(gpr_buf));
+	memset(fpr_buf, 0, sizeof(fpr_buf));
 
-	asm __volatile__(
-		ASM_LOAD_GPR_IMMED(gpr_1)
-		ASM_LOAD_FPR(flt_1)
-		:
-		: [gpr_1]"i"(GPR_1), [flt_1] "b" (&a)
-		: "memory", "r6", "r7", "r8", "r9", "r10",
-		"r11", "r12", "r13", "r14", "r15", "r16", "r17",
-		"r18", "r19", "r20", "r21", "r22", "r23", "r24",
-		"r25", "r26", "r27", "r28", "r29", "r30", "r31"
-		);
-
-	cptr[1] = 1;
+	for (i = 0; i < 32; i++) {
+		gpr_buf[i] = GPR_1;
+		fpr_buf[i] = a;
+	}
 
-	while (!cptr[0])
-		asm volatile("" : : : "memory");
+	gpr_child_loop(&cptr[0], &cptr[1], gpr_buf, fpr_buf);
 
 	shmdt((void *)cptr);
-	store_gpr(gpr_buf);
-	store_fpr(fpr_buf);
 
 	if (validate_gpr(gpr_buf, GPR_3))
 		exit(1);
-- 
2.35.3


  parent reply	other threads:[~2022-06-27 14:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-27 14:02 [PATCH 01/13] selftests/powerpc: Ensure 16-byte stack pointer alignment Michael Ellerman
2022-06-27 14:02 ` [PATCH 02/13] selftests/powerpc/ptrace: Set LOCAL_HDRS Michael Ellerman
2022-06-27 14:02 ` [PATCH 03/13] selftests/powerpc/ptrace: Split CFLAGS better Michael Ellerman
2022-06-27 14:02 ` [PATCH 04/13] selftests/powerpc: Don't save CR by default in asm helpers Michael Ellerman
2022-06-27 14:02 ` [PATCH 05/13] selftests/powerpc: Don't save TOC " Michael Ellerman
2022-06-27 14:02 ` [PATCH 06/13] selftests/powerpc: Add 32-bit support to " Michael Ellerman
2022-06-27 14:02 ` [PATCH 07/13] selftests/powerpc/ptrace: Drop unused load_fpr_single_precision() Michael Ellerman
2022-06-27 14:02 ` [PATCH 08/13] selftests/powerpc/ptrace: Convert to load/store doubles Michael Ellerman
2022-06-27 14:02 ` [PATCH 09/13] selftests/powerpc/ptrace: Build the ptrace-gpr test as 32-bit when possible Michael Ellerman
2022-06-27 14:02 ` Michael Ellerman [this message]
2022-06-27 14:02 ` [PATCH 11/13] selftests/powerpc/ptrace: Make child errors more obvious Michael Ellerman
2022-06-27 14:02 ` [PATCH 12/13] selftests/powerpc/ptrace: Use more interesting values Michael Ellerman
2022-06-27 14:02 ` [PATCH 13/13] selftests/powerpc/ptrace: Add peek/poke of FPRs Michael Ellerman
2022-07-29 13:02 ` [PATCH 01/13] selftests/powerpc: Ensure 16-byte stack pointer alignment Michael Ellerman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220627140239.2464900-10-mpe@ellerman.id.au \
    --to=mpe@ellerman.id.au \
    --cc=linuxppc-dev@lists.ozlabs.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.