[glibc/arm/morello/main] TODO(gprof): aarch64: morello: add gprof profiling support to asm

[glibc/arm/morello/main] TODO(gprof): aarch64: morello: add gprof profiling support to asm

[Szabolcs Nagy]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ccce788403ca63581a3ab08b619368223ed2502e

commit ccce788403ca63581a3ab08b619368223ed2502e
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Wed Jul 13 15:22:10 2022 +0100

    TODO(gprof): aarch64: morello: add gprof profiling support to asm
    
    Assembly prologue code with mcount call for gprof instrumentation.
    
    TODO: untested, likely needs further runtime updates too.

Diff:
---
 sysdeps/aarch64/sysdep.h | 42 ++++++++++++++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/sysdeps/aarch64/sysdep.h b/sysdeps/aarch64/sysdep.h
index 6575503c8b..eb58ee340d 100644
--- a/sysdeps/aarch64/sysdep.h
+++ b/sysdeps/aarch64/sysdep.h
@@ -151,10 +151,44 @@ GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI)
   ASM_SIZE_DIRECTIVE(name)
 
 /* If compiled for profiling, call `mcount' at the start of each function.  */
-#ifdef	PROF
-# ifdef __CHERI_PURE_CAPABILITY__
-#  error mcount profiling is not supported with purecap ABI
-# endif
+#if defined PROF && defined __CHERI_PURE_CAPABILITY__
+/* Note: c9 must be preserved in var arg functions.  */
+# define CALL_MCOUNT						\
+	stp	c30, c9, [csp, #-160]!;				\
+	cfi_adjust_cfa_offset (160);				\
+	cfi_rel_offset (c30, 0);				\
+	cfi_rel_offset (c9, 16);				\
+	stp	c0, c1, [csp, #32];				\
+	cfi_rel_offset (c0, 32);				\
+	cfi_rel_offset (c1, 48);				\
+	stp	c2, c3, [csp, #64];				\
+	cfi_rel_offset (c2, 64);				\
+	cfi_rel_offset (c3, 80);				\
+	stp	c4, c5, [csp, #96];				\
+	cfi_rel_offset (c4, 96);				\
+	cfi_rel_offset (c5, 112);				\
+	stp	c6, c7, [csp, #128];				\
+	cfi_rel_offset (c6, 128);				\
+	cfi_rel_offset (c7, 144);				\
+	mov	c0, c30;					\
+	bl	mcount;						\
+	ldp	c0, c1, [csp, #32];				\
+	cfi_restore (c0);					\
+	cfi_restore (c1);					\
+	ldp	c2, c3, [csp, #64];				\
+	cfi_restore (c2);					\
+	cfi_restore (c3);					\
+	ldp	c4, c5, [csp, #96];				\
+	cfi_restore (c4);					\
+	cfi_restore (c5);					\
+	ldp	c6, c7, [csp, #128];				\
+	cfi_restore (c6);					\
+	cfi_restore (c7);					\
+	ldp	c30, c9, [csp, #160];				\
+	cfi_adjust_cfa_offset (-160);				\
+	cfi_restore (c30);					\
+	cfi_restore (c9);
+#elif defined PROF && !defined __CHERI_PURE_CAPAILITY__
 # define CALL_MCOUNT						\
 	str	x30, [sp, #-80]!;				\
 	cfi_adjust_cfa_offset (80);				\