Merge branch 'libucontext-ppc64' into 'master'

Libucontext ppc64

Fix libucontext functions for ppc64

See merge request !185

1 files changed, 105 insertions, 0 deletions

diff --git a/system/libucontext/ppc64-stack-layout.patch b/system/libucontext/ppc64-stack-layout.patch
new file mode 100644
index 000000000..d030b61af
--- /dev/null
+++ b/system/libucontext/ppc64-stack-layout.patch
@@ -0,0 +1,105 @@
+From a17b01bc9df4004a1852ba272d452b0f46f5927c Mon Sep 17 00:00:00 2001
+From: Bobby Bingham <koorogi@koorogi.info>
+Date: Tue, 19 Feb 2019 06:27:28 +0000
+Subject: [PATCH 3/3] ppc64: fix stack frame layout
+
+---
+ arch/ppc64/makecontext.c | 48 +++++++++++++++++-----------------------
+ 1 file changed, 20 insertions(+), 28 deletions(-)
+
+diff --git a/arch/ppc64/makecontext.c b/arch/ppc64/makecontext.c
+index 9d6b998..6d9841c 100644
+--- a/arch/ppc64/makecontext.c
++++ b/arch/ppc64/makecontext.c
+@@ -1,5 +1,6 @@
+ /*
+  * Copyright (c) 2018 William Pitcock <nenolod@dereferenced.org>
++ * Copyright (c) 2019 Bobby Bingham <koorogi@koorogi.info>
+  *
+  * Permission to use, copy, modify, and/or distribute this software for any
+  * purpose with or without fee is hereby granted, provided that the above
+@@ -11,32 +12,39 @@
+  */
+ 
+ #define _GNU_SOURCE
+-#include <stddef.h>
+ #include <stdarg.h>
+ #include <signal.h>
+-#include <string.h>
+ #include <stdint.h>
+ 
+-
+ #include "defs.h"
+ 
+ 
+ extern void __start_context(void);
+ 
+ 
++#define SAVEARG(i,val) \
++	do { \
++		*(i < 8 ? &ucp->uc_mcontext.gp_regs[3+i] : argp) = val; \
++		argp++; \
++	} while (0)
++
+ void
+ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+ {
+ 	greg_t *sp, *argp;
+ 	va_list va;
+-	int i;
+-	unsigned int uc_link, stack_args;
++	unsigned int stack_args;
++
++	/* We pass uc_link as an argument, so in total we have argc+1 args */
++	stack_args = argc + 1;
+ 
+-	stack_args = argc > 8 ? argc - 8 : 0;
+-	uc_link = stack_args + 1;
++	/* We can pass 8 args before needing the stack.  If any arg is passed
++	 * on the stack, then stack space must be reserved for all args, even
++	 * though the first 8 don't need to be stored there */
++	if (stack_args <= 8) stack_args = 0;
+ 
+ 	sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
+-	sp -= (uc_link + 1);
++	sp -= stack_args + 4;
+ 	sp = (greg_t *) (((uintptr_t) sp & -16L));
+ 
+ 	ucp->uc_mcontext.gp_regs[REG_NIP]   = (uintptr_t) func;
+@@ -45,29 +53,13 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+ 	ucp->uc_mcontext.gp_regs[REG_ENTRY] = (uintptr_t) func;
+ 	ucp->uc_mcontext.gp_regs[REG_R31]   = (uintptr_t) ucp->uc_link;
+ 
+-	sp[0] = (uintptr_t) &__start_context;
+-	sp[uc_link] = (uintptr_t) ucp->uc_link;
+-	argp = &sp[2];
++	sp[0] = 0;
++	argp = &sp[4];
+ 
+ 	va_start(va, argc);
+ 
+-	for (i = 0; i < argc; i++)
+-		switch (i)
+-		{
+-		case 0:
+-		case 1:
+-		case 2:
+-		case 3:
+-		case 4:
+-		case 5:
+-		case 6:
+-		case 7:
+-			ucp->uc_mcontext.gp_regs[i + 3] = va_arg (va, greg_t);
+-			break;
+-		default:
+-			*argp++ = va_arg (va, greg_t);
+-			break;
+-		}
++	for (int i = 0; i < argc; i++) SAVEARG(i, va_arg(va, greg_t));
++	SAVEARG(argc, (uintptr_t) ucp->uc_link);
+ 
+ 	va_end(va);
+ }
+-- 
+2.19.2
+