From 9ac8822b66bb06a463a29ec86088cfe8adc1e6d4 Mon Sep 17 00:00:00 2001
From: Jiajie Li <lijiajie11@huawei.com>
Date: Mon, 12 Oct 2020 14:45:03 +0800
Subject: [PATCH 34/89] kpatch_coro: Split function locate_start_context_symbol

The function locate_start_context_symbol is arch related, so let's
make two separate definations in arch/x86/arch_coro.c and
arch/aarch64/arch_coro.c

Signed-off-by: Jiajie Li <lijiajie11@huawei.com>
Signed-off-by: Ying Fang <fangying1@huawei.com>
---
 src/arch/aarch64/arch_coro.c | 63 ++++++++++++++++++++++++++
 src/arch/x86/arch_coro.c     | 67 +++++++++++++++++++++++++++
 src/include/kpatch_coro.h    | 21 +++++++++
 src/kpatch_coro.c            | 87 ------------------------------------
 4 files changed, 151 insertions(+), 87 deletions(-)

diff --git a/src/arch/aarch64/arch_coro.c b/src/arch/aarch64/arch_coro.c
index b93581e..f485cf9 100644
--- a/src/arch/aarch64/arch_coro.c
+++ b/src/arch/aarch64/arch_coro.c
@@ -11,6 +11,69 @@
 #include "include/kpatch_ptrace.h"
 #include "include/kpatch_log.h"
 
+asm (
+    "makecontext_call:\n"
+    "mov x29, sp\n"
+    "and x29,x29,#-16\n"
+    "sub x29, x29,#0x400\n"
+    "ldr x9,[x29,#-128]\n"
+    "str x9,[fp,#0x10]\n"
+    //"str #128,[fp.#0x20]\n"
+    "mov x0,fp\n"
+    "mov x1,#0x100\n"
+    "mov x2,#0\n"
+    "svc #0\n"
+    "brk #0\n"
+    "makecontext_call_end:"
+    );
+
+extern unsigned char makecontext_call, makecontext_call_end;
+
+int
+locate_start_context_symbol(struct kpatch_process *proc,
+			    unsigned long *pstart_context)
+{
+	struct object_file *olibc;
+	struct user_regs_struct regs;
+	int rv;
+	unsigned long makecontext;
+
+	olibc = kpatch_process_get_obj_by_regex(proc, "^libc-.*\\.so");
+	if (olibc == NULL) {
+		kpdebug("FAIL. Can't find libc\n");
+		return -1;
+	}
+
+	rv = kpatch_resolve_undefined_single_dynamic(olibc,
+						     "makecontext",
+						     &makecontext);
+	makecontext = vaddr2addr(olibc, makecontext);
+	if (rv < 0 || makecontext == 0) {
+		kpdebug("FAIL. Can't find makecontext\n");
+		return -1;
+	}
+
+	regs.regs[8] = makecontext;
+	rv = kpatch_execute_remote(proc2pctx(proc),
+				   &makecontext_call,
+				   &makecontext_call_end - &makecontext_call,
+				   &regs);
+	if (rv < 0) {
+		kpdebug("FAIL. Can't execute makecontext\n");
+		return -1;
+	}
+
+	rv = kpatch_process_mem_read(proc,
+				     regs.regs[29]- STACK_OFFSET_START_CONTEXT,
+				     pstart_context,
+				     sizeof(*pstart_context));
+	if (rv < 0) {
+		kpdebug("FAIL. Can't peek __start_context address\n");
+		return -1;
+	}
+	return rv;
+}
+
 int get_ptr_guard(struct kpatch_process *proc,
 			 unsigned long *ptr_guard)
 {
diff --git a/src/arch/x86/arch_coro.c b/src/arch/x86/arch_coro.c
index 86bf12f..27c834b 100644
--- a/src/arch/x86/arch_coro.c
+++ b/src/arch/x86/arch_coro.c
@@ -15,6 +15,73 @@
 #include "include/kpatch_ptrace.h"
 #include "include/kpatch_log.h"
 
+asm ("makecontext_call:\n"
+     "mov %rsp, %rbp\n"
+     "and $-16, %rbp\n"
+     /* ucontext_t is 0x3a8 bytes */
+     "sub $0x400, %rbp\n"
+     /* TODO interpolate these from the calculations above */
+
+     /* set uc_stack.ss_sp and uc_stack.ss_size */
+     /* TODO magic -128 is used below as well */
+     "lea -128(%rbp), %rbx\n"
+     "movq %rbx, 0x10(%rbp)\n"
+     "movq $128, 0x20(%rbp)\n"
+     "mov %rbp, %rdi\n"
+     "mov $0x100, %rsi\n"
+     "xor %rdx, %rdx\n"
+     /* call `makecontext` */
+     "call *%rax\n"
+     "int3\n"
+     "makecontext_call_end:");
+
+extern unsigned char makecontext_call, makecontext_call_end;
+
+int
+locate_start_context_symbol(struct kpatch_process *proc,
+			    unsigned long *pstart_context)
+{
+	struct object_file *olibc;
+	struct user_regs_struct regs;
+	int rv;
+	unsigned long makecontext;
+
+	olibc = kpatch_process_get_obj_by_regex(proc, "^libc-.*\\.so");
+	if (olibc == NULL) {
+		kpdebug("FAIL. Can't find libc\n");
+		return -1;
+	}
+
+	rv = kpatch_resolve_undefined_single_dynamic(olibc,
+						     "makecontext",
+						     &makecontext);
+	makecontext = vaddr2addr(olibc, makecontext);
+	if (rv < 0 || makecontext == 0) {
+		kpdebug("FAIL. Can't find makecontext\n");
+		return -1;
+	}
+
+	regs.rax = makecontext;
+	rv = kpatch_execute_remote(proc2pctx(proc),
+				   &makecontext_call,
+				   &makecontext_call_end - &makecontext_call,
+				   &regs);
+	if (rv < 0) {
+		kpdebug("FAIL. Can't execute makecontext\n");
+		return -1;
+	}
+
+	rv = kpatch_process_mem_read(proc,
+				     regs.rbp - STACK_OFFSET_START_CONTEXT,
+				     pstart_context,
+				     sizeof(*pstart_context));
+	if (rv < 0) {
+		kpdebug("FAIL. Can't peek __start_context address\n");
+		return -1;
+	}
+	return rv;
+}
+
 int get_ptr_guard(struct kpatch_process *proc,
 			 unsigned long *ptr_guard)
 {
diff --git a/src/include/kpatch_coro.h b/src/include/kpatch_coro.h
index 272855e..0b3a9a1 100644
--- a/src/include/kpatch_coro.h
+++ b/src/include/kpatch_coro.h
@@ -30,10 +30,31 @@ struct UCORO_info {
 int _UCORO_access_reg(unw_addr_space_t as, unw_regnum_t reg,
 					unw_word_t *val, int write, void *arg);
 
+#define PTR_DEMANGLE(ptr, key) ((((ptr) >> 0x11) | ((ptr) << 47)) ^ key)
+#define JB_RBX 0
+#define JB_RBP 1
+#define JB_R12 2
+#define JB_R13 3
+#define JB_R14 4
+#define JB_R15 5
+#define JB_RSP 6
+#define JB_RIP 7
+
+#define STACK_OFFSET_UC_LINK (2 * sizeof(long))
+#define STACK_OFFSET_START_CONTEXT (3 * sizeof(long))
+#define STACK_OFFSET_UC_LINK_PTR (4 * sizeof(long))
+#define STACK_OFFSET_COROUTINE_UCONTEXT (7 * sizeof(long))
+#define STACK_OFFSET_COROUTINE (8 * sizeof(long))
+
+#define UCONTEXT_OFFSET_JMPBUF 0x38
+
 #define GLIBC_TLS_PTR_GUARD 0x30
 int get_ptr_guard(struct kpatch_process *proc,
 					unsigned long *ptr_guard);
 
+int locate_start_context_symbol(struct kpatch_process *proc,
+					unsigned long *pstart_context);
+
 
 int kpatch_coroutines_init(struct kpatch_process *proc);
 int kpatch_coroutines_find(struct kpatch_process *proc);
diff --git a/src/kpatch_coro.c b/src/kpatch_coro.c
index ea4050f..8457800 100644
--- a/src/kpatch_coro.c
+++ b/src/kpatch_coro.c
@@ -95,93 +95,6 @@ kpatch_coro_free(struct kpatch_coro *c)
  * some kind of persistency (to allow kernelcare updates). This
  * service also can listen to netlink events about new processes.
  */
-#define PTR_DEMANGLE(ptr, key) ((((ptr) >> 0x11) | ((ptr) << 47)) ^ key)
-#define JB_RBX 0
-#define JB_RBP 1
-#define JB_R12 2
-#define JB_R13 3
-#define JB_R14 4
-#define JB_R15 5
-#define JB_RSP 6
-#define JB_RIP 7
-
-#define STACK_OFFSET_UC_LINK (2 * sizeof(long))
-#define STACK_OFFSET_START_CONTEXT (3 * sizeof(long))
-#define STACK_OFFSET_UC_LINK_PTR (4 * sizeof(long))
-#define STACK_OFFSET_COROUTINE_UCONTEXT (7 * sizeof(long))
-#define STACK_OFFSET_COROUTINE (8 * sizeof(long))
-
-#define UCONTEXT_OFFSET_JMPBUF 0x38
-
-#define UCONTEXT_OFFSET_UC_STACK_SS_SP		offsetof(ucontext_t, uc_stack.ss_sp)
-#define UCONTEXT_OFFSET_UC_STACK_SS_SIZE	offsetof(ucontext_t, uc_stack.ss_size)
-
-asm ("makecontext_call:\n"
-     "mov %rsp, %rbp\n"
-     "and $-16, %rbp\n"
-     /* ucontext_t is 0x3a8 bytes */
-     "sub $0x400, %rbp\n"
-     /* TODO interpolate these from the calculations above */
-
-     /* set uc_stack.ss_sp and uc_stack.ss_size */
-     /* TODO magic -128 is used below as well */
-     "lea -128(%rbp), %rbx\n"
-     "movq %rbx, 0x10(%rbp)\n"
-     "movq $128, 0x20(%rbp)\n"
-     "mov %rbp, %rdi\n"
-     "mov $0x100, %rsi\n"
-     "xor %rdx, %rdx\n"
-     /* call `makecontext` */
-     "call *%rax\n"
-     "int3\n"
-     "makecontext_call_end:");
-
-extern unsigned char makecontext_call, makecontext_call_end;
-
-static int
-locate_start_context_symbol(struct kpatch_process *proc,
-			    unsigned long *pstart_context)
-{
-	struct object_file *olibc;
-	struct user_regs_struct regs;
-	int rv;
-	unsigned long makecontext;
-
-	olibc = kpatch_process_get_obj_by_regex(proc, "^libc-.*\\.so");
-	if (olibc == NULL) {
-		kpdebug("FAIL. Can't find libc\n");
-		return -1;
-	}
-
-	rv = kpatch_resolve_undefined_single_dynamic(olibc,
-						     "makecontext",
-						     &makecontext);
-	makecontext = vaddr2addr(olibc, makecontext);
-	if (rv < 0 || makecontext == 0) {
-		kpdebug("FAIL. Can't find makecontext\n");
-		return -1;
-	}
-
-	regs.rax = makecontext;
-	rv = kpatch_execute_remote(proc2pctx(proc),
-				   &makecontext_call,
-				   &makecontext_call_end - &makecontext_call,
-				   &regs);
-	if (rv < 0) {
-		kpdebug("FAIL. Can't execute makecontext\n");
-		return -1;
-	}
-
-	rv = kpatch_process_mem_read(proc,
-				     regs.rbp - STACK_OFFSET_START_CONTEXT,
-				     pstart_context,
-				     sizeof(*pstart_context));
-	if (rv < 0) {
-		kpdebug("FAIL. Can't peek __start_context address\n");
-		return -1;
-	}
-	return rv;
-}
 
 static int is_test_target(struct kpatch_process *proc,
 			  const char *procname)
-- 
2.23.0