diff options
Diffstat (limited to 'system/libucontext/powerpc.patch')
| -rw-r--r-- | system/libucontext/powerpc.patch | 583 |
1 files changed, 583 insertions, 0 deletions
diff --git a/system/libucontext/powerpc.patch b/system/libucontext/powerpc.patch new file mode 100644 index 000000000..e6df4cf25 --- /dev/null +++ b/system/libucontext/powerpc.patch @@ -0,0 +1,583 @@ +From 2610c7faa7b9c4114d53bb659264a6be238cd2a3 Mon Sep 17 00:00:00 2001 +From: Bobby Bingham <koorogi@koorogi.info> +Date: Sat, 23 Feb 2019 17:12:37 -0600 +Subject: [PATCH] ppc32/64: rewrite get/set/swapcontext in assembly + +getcontext cannot be correctly implemented in C. + +If this calls another function, as it does to call syscall, it needs to +first spill its return address to the stack. If, after getcontext returns, +its caller then calls other functions, this saved return address can be +clobbered. When the context saved by getcontext is later restored, the +(now clobbered) return address will be reloaded from the stack, and the +second return from getcontext will return to the wrong location. + +Because the powerpc swapcontext syscall allows either the old context or +new context pointers to be null, it is usable for implementing all of +get/set/swapcontext. + +We therefore rewrite swapcontext in assembly, and get/setcontext as simple +assembly function wrappers around swapcontext. + +The one piece we keep in C is the code to check the return value of the +system call and to set errno. This code was actually unnecessary before -- +libc does this within syscall. However, now that the system call is made +directly in assembly, bypassing libc, it is truly necessary. Because errno +is thread-local and the details of how to set it can vary by libc, this +code remains written in C. +--- + Makefile | 10 +---- + README.md | 2 +- + arch/ppc/getcontext.S | 20 +++++++++ + arch/ppc/{getcontext.c => retfromsyscall.c} | 30 +++---------- + arch/ppc/setcontext.S | 21 +++++++++ + arch/ppc/setcontext.c | 45 ------------------- + arch/ppc/swapcontext.S | 23 ++++++++++ + arch/ppc/swapcontext.c | 45 ------------------- + arch/ppc64/getcontext.S | 25 +++++++++++ + arch/ppc64/{getcontext.c => retfromsyscall.c} | 30 +++---------- + arch/ppc64/setcontext.S | 26 +++++++++++ + arch/ppc64/setcontext.c | 45 ------------------- + arch/ppc64/swapcontext.S | 28 ++++++++++++ + arch/ppc64/swapcontext.c | 45 ------------------- + 14 files changed, 156 insertions(+), 239 deletions(-) + create mode 100644 arch/ppc/getcontext.S + rename arch/ppc/{getcontext.c => retfromsyscall.c} (53%) + create mode 100644 arch/ppc/setcontext.S + delete mode 100644 arch/ppc/setcontext.c + create mode 100644 arch/ppc/swapcontext.S + delete mode 100644 arch/ppc/swapcontext.c + create mode 100644 arch/ppc64/getcontext.S + rename arch/ppc64/{getcontext.c => retfromsyscall.c} (53%) + create mode 100644 arch/ppc64/setcontext.S + delete mode 100644 arch/ppc64/setcontext.c + create mode 100644 arch/ppc64/swapcontext.S + delete mode 100644 arch/ppc64/swapcontext.c + +diff --git a/Makefile b/Makefile +index 51365a3..d6ff1b0 100644 +--- a/Makefile ++++ b/Makefile +@@ -2,14 +2,8 @@ ARCH := $(shell uname -m) + + CFLAGS = -ggdb3 -O2 -Wall -Iarch/${ARCH} + +-LIBUCONTEXT_C_SRC = \ +- arch/${ARCH}/makecontext.c +- +-LIBUCONTEXT_S_SRC = \ +- arch/${ARCH}/getcontext.S \ +- arch/${ARCH}/setcontext.S \ +- arch/${ARCH}/swapcontext.S \ +- arch/${ARCH}/startcontext.S ++LIBUCONTEXT_C_SRC = $(wildcard arch/${ARCH}/*.c) ++LIBUCONTEXT_S_SRC = $(wildcard arch/${ARCH}/*.S) + + LIBUCONTEXT_OBJ = ${LIBUCONTEXT_C_SRC:.c=.o} ${LIBUCONTEXT_S_SRC:.S=.o} + LIBUCONTEXT_SOVERSION = 0 +diff --git a/README.md b/README.md +index 6bd4493..27d3d0b 100644 +--- a/README.md ++++ b/README.md +@@ -19,7 +19,7 @@ Right now these archs are supported and should work on bare metal: + * aarch64 + * s390x + +-These archs require kernel assistance and use a syscall (the only assembly is the trampoline): ++These archs require kernel assistance and use a syscall: + + * ppc + * ppc64 (ELFv2 ABI spec only, ELFv1 not supported) +diff --git a/arch/ppc/getcontext.S b/arch/ppc/getcontext.S +new file mode 100644 +index 0000000..beffaf5 +--- /dev/null ++++ b/arch/ppc/getcontext.S +@@ -0,0 +1,20 @@ ++/* ++ * 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 ++ * copyright notice and this permission notice appear in all copies. ++ * ++ * This software is provided 'as is' and without any warranty, express or ++ * implied. In no event shall the authors be liable for any damages arising ++ * from the use of this software. ++ */ ++ ++.global __getcontext ++.hidden __swapcontext ++__getcontext: ++ li 4, 0 ++ b __swapcontext@local ++ ++.weak getcontext ++getcontext = __getcontext +diff --git a/arch/ppc/getcontext.c b/arch/ppc/retfromsyscall.c +similarity index 53% +rename from arch/ppc/getcontext.c +rename to arch/ppc/retfromsyscall.c +index 5da9dfb..3ad43c0 100644 +--- a/arch/ppc/getcontext.c ++++ b/arch/ppc/retfromsyscall.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 +@@ -10,36 +11,15 @@ + * from the use of this software. + */ + +-#define _GNU_SOURCE +-#include <stddef.h> +-#include <stdarg.h> +-#include <signal.h> +-#include <string.h> +-#include <stdint.h> + #include <errno.h> +-#include <unistd.h> +-#include <sys/syscall.h> + +- +-int +-__getcontext(ucontext_t *ucp) ++__attribute__ ((visibility ("hidden"))) ++int __retfromsyscall(long retval) + { +-#ifdef SYS_swapcontext +- int r; +- +- r = syscall(SYS_swapcontext, ucp, NULL, sizeof(ucontext_t)); +- if (r < 0) +- { +- errno = -r; ++ if (retval < 0) { ++ errno = -retval; + return -1; + } +- + return 0; +-#else +- errno = ENOSYS; +- return -1; +-#endif + } + +- +-extern __typeof(__getcontext) getcontext __attribute__((weak, __alias__("__getcontext"))); +diff --git a/arch/ppc/setcontext.S b/arch/ppc/setcontext.S +new file mode 100644 +index 0000000..89e6de0 +--- /dev/null ++++ b/arch/ppc/setcontext.S +@@ -0,0 +1,21 @@ ++/* ++ * 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 ++ * copyright notice and this permission notice appear in all copies. ++ * ++ * This software is provided 'as is' and without any warranty, express or ++ * implied. In no event shall the authors be liable for any damages arising ++ * from the use of this software. ++ */ ++ ++.global __setcontext ++.hidden __swapcontext ++__setcontext: ++ mr 4, 3 ++ li 3, 0 ++ b __swapcontext@local ++ ++.weak setcontext ++setcontext = __setcontext +diff --git a/arch/ppc/setcontext.c b/arch/ppc/setcontext.c +deleted file mode 100644 +index 59c65b4..0000000 +--- a/arch/ppc/setcontext.c ++++ /dev/null +@@ -1,45 +0,0 @@ +-/* +- * Copyright (c) 2018 William Pitcock <nenolod@dereferenced.org> +- * +- * Permission to use, copy, modify, and/or distribute this software for any +- * purpose with or without fee is hereby granted, provided that the above +- * copyright notice and this permission notice appear in all copies. +- * +- * This software is provided 'as is' and without any warranty, express or +- * implied. In no event shall the authors be liable for any damages arising +- * from the use of this software. +- */ +- +-#define _GNU_SOURCE +-#include <stddef.h> +-#include <stdarg.h> +-#include <signal.h> +-#include <string.h> +-#include <stdint.h> +-#include <errno.h> +-#include <unistd.h> +-#include <sys/syscall.h> +- +- +-int +-__setcontext(const ucontext_t *ucp) +-{ +-#ifdef SYS_swapcontext +- int r; +- +- r = syscall(SYS_swapcontext, NULL, (void *) ucp, sizeof(ucontext_t)); +- if (r < 0) +- { +- errno = -r; +- return -1; +- } +- +- return r; +-#else +- errno = ENOSYS; +- return -1; +-#endif +-} +- +- +-extern __typeof(__setcontext) setcontext __attribute__((weak, __alias__("__setcontext"))); +diff --git a/arch/ppc/swapcontext.S b/arch/ppc/swapcontext.S +new file mode 100644 +index 0000000..24b6655 +--- /dev/null ++++ b/arch/ppc/swapcontext.S +@@ -0,0 +1,23 @@ ++/* ++ * 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 ++ * copyright notice and this permission notice appear in all copies. ++ * ++ * This software is provided 'as is' and without any warranty, express or ++ * implied. In no event shall the authors be liable for any damages arising ++ * from the use of this software. ++ */ ++ ++.global __swapcontext ++__swapcontext: ++ li 0, 249 # SYS_swapcontext ++ li 5, 1184 # sizeof(ucontext_t) ++ sc ++ ++.hidden __retfromsyscall ++ b __retfromsyscall@local ++ ++.weak swapcontext ++swapcontext = __swapcontext +diff --git a/arch/ppc/swapcontext.c b/arch/ppc/swapcontext.c +deleted file mode 100644 +index af14bc2..0000000 +--- a/arch/ppc/swapcontext.c ++++ /dev/null +@@ -1,45 +0,0 @@ +-/* +- * Copyright (c) 2018 William Pitcock <nenolod@dereferenced.org> +- * +- * Permission to use, copy, modify, and/or distribute this software for any +- * purpose with or without fee is hereby granted, provided that the above +- * copyright notice and this permission notice appear in all copies. +- * +- * This software is provided 'as is' and without any warranty, express or +- * implied. In no event shall the authors be liable for any damages arising +- * from the use of this software. +- */ +- +-#define _GNU_SOURCE +-#include <stddef.h> +-#include <stdarg.h> +-#include <signal.h> +-#include <string.h> +-#include <stdint.h> +-#include <errno.h> +-#include <unistd.h> +-#include <sys/syscall.h> +- +- +-int +-__swapcontext(ucontext_t *oucp, const ucontext_t *ucp) +-{ +-#ifdef SYS_swapcontext +- int r; +- +- r = syscall(SYS_swapcontext, oucp, ucp, sizeof(ucontext_t)); +- if (r < 0) +- { +- errno = -r; +- return -1; +- } +- +- return r; +-#else +- errno = ENOSYS; +- return -1; +-#endif +-} +- +- +-extern __typeof(__swapcontext) swapcontext __attribute__((weak, __alias__("__swapcontext"))); +diff --git a/arch/ppc64/getcontext.S b/arch/ppc64/getcontext.S +new file mode 100644 +index 0000000..935edd2 +--- /dev/null ++++ b/arch/ppc64/getcontext.S +@@ -0,0 +1,25 @@ ++/* ++ * 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 ++ * copyright notice and this permission notice appear in all copies. ++ * ++ * This software is provided 'as is' and without any warranty, express or ++ * implied. In no event shall the authors be liable for any damages arising ++ * from the use of this software. ++ */ ++ ++.global __getcontext ++.hidden __swapcontext ++__getcontext: ++ addis 2, 12, .TOC.-__getcontext@ha ++ addi 2, 12, .TOC.-__getcontext@l ++ ++ .localentry __getcontext,.-__getcontext ++ ++ li 4, 0 ++ b __swapcontext ++ ++.weak getcontext ++getcontext = __getcontext +diff --git a/arch/ppc64/getcontext.c b/arch/ppc64/retfromsyscall.c +similarity index 53% +rename from arch/ppc64/getcontext.c +rename to arch/ppc64/retfromsyscall.c +index 5da9dfb..3ad43c0 100644 +--- a/arch/ppc64/getcontext.c ++++ b/arch/ppc64/retfromsyscall.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 +@@ -10,36 +11,15 @@ + * from the use of this software. + */ + +-#define _GNU_SOURCE +-#include <stddef.h> +-#include <stdarg.h> +-#include <signal.h> +-#include <string.h> +-#include <stdint.h> + #include <errno.h> +-#include <unistd.h> +-#include <sys/syscall.h> + +- +-int +-__getcontext(ucontext_t *ucp) ++__attribute__ ((visibility ("hidden"))) ++int __retfromsyscall(long retval) + { +-#ifdef SYS_swapcontext +- int r; +- +- r = syscall(SYS_swapcontext, ucp, NULL, sizeof(ucontext_t)); +- if (r < 0) +- { +- errno = -r; ++ if (retval < 0) { ++ errno = -retval; + return -1; + } +- + return 0; +-#else +- errno = ENOSYS; +- return -1; +-#endif + } + +- +-extern __typeof(__getcontext) getcontext __attribute__((weak, __alias__("__getcontext"))); +diff --git a/arch/ppc64/setcontext.S b/arch/ppc64/setcontext.S +new file mode 100644 +index 0000000..5a0cde3 +--- /dev/null ++++ b/arch/ppc64/setcontext.S +@@ -0,0 +1,26 @@ ++/* ++ * 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 ++ * copyright notice and this permission notice appear in all copies. ++ * ++ * This software is provided 'as is' and without any warranty, express or ++ * implied. In no event shall the authors be liable for any damages arising ++ * from the use of this software. ++ */ ++ ++.global __setcontext ++.hidden __swapcontext ++__setcontext: ++ addis 2, 12, .TOC.-__setcontext@ha ++ addi 2, 12, .TOC.-__setcontext@l ++ ++ .localentry __setcontext,.-__setcontext ++ ++ mr 4, 3 ++ li 3, 0 ++ b __swapcontext ++ ++.weak setcontext ++setcontext = __setcontext +diff --git a/arch/ppc64/setcontext.c b/arch/ppc64/setcontext.c +deleted file mode 100644 +index 59c65b4..0000000 +--- a/arch/ppc64/setcontext.c ++++ /dev/null +@@ -1,45 +0,0 @@ +-/* +- * Copyright (c) 2018 William Pitcock <nenolod@dereferenced.org> +- * +- * Permission to use, copy, modify, and/or distribute this software for any +- * purpose with or without fee is hereby granted, provided that the above +- * copyright notice and this permission notice appear in all copies. +- * +- * This software is provided 'as is' and without any warranty, express or +- * implied. In no event shall the authors be liable for any damages arising +- * from the use of this software. +- */ +- +-#define _GNU_SOURCE +-#include <stddef.h> +-#include <stdarg.h> +-#include <signal.h> +-#include <string.h> +-#include <stdint.h> +-#include <errno.h> +-#include <unistd.h> +-#include <sys/syscall.h> +- +- +-int +-__setcontext(const ucontext_t *ucp) +-{ +-#ifdef SYS_swapcontext +- int r; +- +- r = syscall(SYS_swapcontext, NULL, (void *) ucp, sizeof(ucontext_t)); +- if (r < 0) +- { +- errno = -r; +- return -1; +- } +- +- return r; +-#else +- errno = ENOSYS; +- return -1; +-#endif +-} +- +- +-extern __typeof(__setcontext) setcontext __attribute__((weak, __alias__("__setcontext"))); +diff --git a/arch/ppc64/swapcontext.S b/arch/ppc64/swapcontext.S +new file mode 100644 +index 0000000..982537a +--- /dev/null ++++ b/arch/ppc64/swapcontext.S +@@ -0,0 +1,28 @@ ++/* ++ * 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 ++ * copyright notice and this permission notice appear in all copies. ++ * ++ * This software is provided 'as is' and without any warranty, express or ++ * implied. In no event shall the authors be liable for any damages arising ++ * from the use of this software. ++ */ ++ ++.global __swapcontext ++__swapcontext: ++ addis 2, 12, .TOC.-__swapcontext@ha ++ addi 2, 12, .TOC.-__swapcontext@l ++ ++ .localentry __swapcontext,.-__swapcontext ++ ++ li 0, 249 # SYS_swapcontext ++ li 5, 1696 # sizeof(ucontext_t) ++ sc ++ ++.hidden __retfromsyscall ++ b __retfromsyscall ++ ++.weak swapcontext ++swapcontext = __swapcontext +diff --git a/arch/ppc64/swapcontext.c b/arch/ppc64/swapcontext.c +deleted file mode 100644 +index af14bc2..0000000 +--- a/arch/ppc64/swapcontext.c ++++ /dev/null +@@ -1,45 +0,0 @@ +-/* +- * Copyright (c) 2018 William Pitcock <nenolod@dereferenced.org> +- * +- * Permission to use, copy, modify, and/or distribute this software for any +- * purpose with or without fee is hereby granted, provided that the above +- * copyright notice and this permission notice appear in all copies. +- * +- * This software is provided 'as is' and without any warranty, express or +- * implied. In no event shall the authors be liable for any damages arising +- * from the use of this software. +- */ +- +-#define _GNU_SOURCE +-#include <stddef.h> +-#include <stdarg.h> +-#include <signal.h> +-#include <string.h> +-#include <stdint.h> +-#include <errno.h> +-#include <unistd.h> +-#include <sys/syscall.h> +- +- +-int +-__swapcontext(ucontext_t *oucp, const ucontext_t *ucp) +-{ +-#ifdef SYS_swapcontext +- int r; +- +- r = syscall(SYS_swapcontext, oucp, ucp, sizeof(ucontext_t)); +- if (r < 0) +- { +- errno = -r; +- return -1; +- } +- +- return r; +-#else +- errno = ENOSYS; +- return -1; +-#endif +-} +- +- +-extern __typeof(__swapcontext) swapcontext __attribute__((weak, __alias__("__swapcontext"))); |