busybox: Fix 1.35 build with clang

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

4 files changed, 52 insertions, 174 deletions

diff --git a/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch b/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch
deleted file mode 100644
index 468a32d..0000000
--- a/recipes-core/busybox/busybox/0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch
+++ /dev/null
@@ -1,172 +0,0 @@
-From d941b59087d34cb93053b638c066bf080122e7bb Mon Sep 17 00:00:00 2001
-From: Khem Raj <raj.khem@gmail.com>
-Date: Wed, 16 Jan 2019 22:39:24 -0800
-Subject: [PATCH] Turn ptr_to_globals and bb_errno to be non const
-
-writing to a const variable is undefined behavior
-
-This is undefined as per (C99 6.7.3 paragraph 5) see [1]
-
-errno and ptr_to_globals is written to in code, this fails with
-segfaults when compiled with clang
-
-unsigned FAST_FUNC bb_strtou(const char *arg, char **endp, int base)
-{
-      unsigned long v;
-      char *endptr;
-
-      if (!endp) endp = &endptr;
-      *endp = (char*) arg;
-
-      if (!isalnum(arg[0])) return ret_ERANGE();
-      errno = 0;
-      v = strtoul(arg, endp, base);
-      if (v > UINT_MAX) return ret_ERANGE();
-      return handle_errors(v, endp);
-  }
-
-without 'const' ( working code )
-
-Dump of assembler code for function bb_strtou:
-   0x0000555555568298 <+0>:     push   %rbx
-   0x0000555555568299 <+1>:     sub    $0x10,%rsp
-   0x000055555556829d <+5>:     test   %rsi,%rsi
-   0x00005555555682a0 <+8>:     lea    0x8(%rsp),%rbx
-   0x00005555555682a5 <+13>:    cmovne %rsi,%rbx
-   0x00005555555682a9 <+17>:    mov    %rdi,(%rbx)
-   0x00005555555682ac <+20>:    mov    (%rdi),%al
-   0x00005555555682ae <+22>:    lea    -0x30(%rax),%ecx
-   0x00005555555682b1 <+25>:    cmp    $0xa,%cl
-   0x00005555555682b4 <+28>:    jb     0x5555555682be <bb_strtou+38>
-   0x00005555555682b6 <+30>:    or     $0x20,%al
-   0x00005555555682b8 <+32>:    add    $0x9f,%al
-   0x00005555555682ba <+34>:    cmp    $0x1a,%al
-   0x00005555555682bc <+36>:    jae    0x5555555682dc <bb_strtou+68>
-   0x00005555555682be <+38>:    mov    0x107da3(%rip),%rax        # 0x555555670068 <bb_errno>
-=> 0x00005555555682c5 <+45>:    movl   $0x0,(%rax)
-   0x00005555555682cb <+51>:    mov    %rbx,%rsi
-   0x00005555555682ce <+54>:    callq  0x555555564310 <strtoul@plt>
-   0x00005555555682d3 <+59>:    mov    %rax,%rcx
-   0x00005555555682d6 <+62>:    shr    $0x20,%rcx
-   0x00005555555682da <+66>:    je     0x5555555682f0 <bb_strtou+88>
-   0x00005555555682dc <+68>:    mov    0x107d85(%rip),%rax        # 0x555555670068 <bb_errno>
-   0x00005555555682e3 <+75>:    movl   $0x22,(%rax)
-   0x00005555555682e9 <+81>:    mov    $0xffffffff,%eax
-   0x00005555555682ee <+86>:    jmp    0x5555555682fb <bb_strtou+99>
-   0x00005555555682f0 <+88>:    mov    %rax,%rdi
-   0x00005555555682f3 <+91>:    mov    %rbx,%rsi
-   0x00005555555682f6 <+94>:    callq  0x5555555681e8 <handle_errors>
-   0x00005555555682fb <+99>:    add    $0x10,%rsp
-   0x00005555555682ff <+103>:   pop    %rbx
-   0x0000555555568300 <+104>:   retq
-
-here address of bb_errno is valid rax = 0x7ffff7cac6c0
-
-with 'const' ( non-working code )
-
-Dump of assembler code for function bb_strtou:
-   0x00005555555682a4 <+0>:     push   %r14
-   0x00005555555682a6 <+2>:     push   %rbx
-   0x00005555555682a7 <+3>:     push   %rax
-   0x00005555555682a8 <+4>:     test   %rsi,%rsi
-   0x00005555555682ab <+7>:     mov    %rsp,%rbx
-   0x00005555555682ae <+10>:    cmovne %rsi,%rbx
-   0x00005555555682b2 <+14>:    mov    %rdi,(%rbx)
-   0x00005555555682b5 <+17>:    mov    (%rdi),%al
-   0x00005555555682b7 <+19>:    lea    -0x30(%rax),%ecx
-   0x00005555555682ba <+22>:    cmp    $0xa,%cl
-   0x00005555555682bd <+25>:    jb     0x5555555682d6 <bb_strtou+50>
-   0x00005555555682bf <+27>:    or     $0x20,%al
-   0x00005555555682c1 <+29>:    add    $0x9f,%al
-   0x00005555555682c3 <+31>:    cmp    $0x1a,%al
-   0x00005555555682c5 <+33>:    jb     0x5555555682d6 <bb_strtou+50>
-   0x00005555555682c7 <+35>:    mov    0x107d9a(%rip),%rax        # 0x555555670068 <bb_errno>
-   0x00005555555682ce <+42>:    movl   $0x22,(%rax)
-   0x00005555555682d4 <+48>:    jmp    0x5555555682fc <bb_strtou+88>
-   0x00005555555682d6 <+50>:    mov    0x107d8b(%rip),%r14        # 0x555555670068 <bb_errno>
-=> 0x00005555555682dd <+57>:    movl   $0x0,(%r14)
-   0x00005555555682e4 <+64>:    mov    %rbx,%rsi
-   0x00005555555682e7 <+67>:    callq  0x555555564300 <strtoul@plt>
-   0x00005555555682ec <+72>:    mov    %rax,%rcx
-   0x00005555555682ef <+75>:    shr    $0x20,%rcx
-   0x00005555555682f3 <+79>:    je     0x555555568303 <bb_strtou+95>
-   0x00005555555682f5 <+81>:    movl   $0x22,(%r14)
-   0x00005555555682fc <+88>:    mov    $0xffffffff,%eax
-   0x0000555555568301 <+93>:    jmp    0x55555556830e <bb_strtou+106>
-   0x0000555555568303 <+95>:    mov    %rax,%rdi
-   0x0000555555568306 <+98>:    mov    %rbx,%rsi
-   0x0000555555568309 <+101>:   callq  0x5555555681f4 <handle_errors>
-   0x000055555556830e <+106>:   add    $0x8,%rsp
-   0x0000555555568312 <+110>:   pop    %rbx
-   0x0000555555568313 <+111>:   pop    %r14
-   0x0000555555568315 <+113>:   retq
-
-r14 is 0x0 and writing to this ofcourse ends up in segfault
-
-[1] https://bugs.llvm.org/show_bug.cgi?id=39919
-
-Signed-off-by: Khem Raj <raj.khem@gmail.com>
----
- coreutils/test.c | 2 +-
- include/libbb.h  | 4 ++--
- libbb/lineedit.c | 2 +-
- shell/ash.c      | 5 ++---
- 4 files changed, 6 insertions(+), 7 deletions(-)
-
---- a/coreutils/test.c
-+++ b/coreutils/test.c
-@@ -435,7 +435,7 @@ struct test_statics {
- };
- 
- /* See test_ptr_hack.c */
--extern struct test_statics *const test_ptr_to_statics;
-+extern struct test_statics *test_ptr_to_statics;
- 
- #define S (*test_ptr_to_statics)
- #define args            (S.args         )
---- a/include/libbb.h
-+++ b/include/libbb.h
-@@ -342,7 +342,7 @@ struct BUG_off_t_size_is_misdetected {
- #if defined(errno)
- /* If errno is a define, assume it's "define errno (*__errno_location())"
-  * and we will cache it's result in this variable */
--extern int *const bb_errno;
-+extern int *bb_errno;
- #undef errno
- #define errno (*bb_errno)
- #define bb_cached_errno_ptr 1
-@@ -2228,7 +2228,7 @@ struct globals;
- /* '*const' ptr makes gcc optimize code much better.
-  * Magic prevents ptr_to_globals from going into rodata.
-  * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */
--extern struct globals *const ptr_to_globals;
-+extern struct globals *ptr_to_globals;
- 
- #if defined(__clang_major__) && __clang_major__ >= 9
- /* Clang/llvm drops assignment to "constant" storage. Silently.
---- a/libbb/lineedit.c
-+++ b/libbb/lineedit.c
-@@ -192,7 +192,7 @@ struct lineedit_statics {
- };
- 
- /* See lineedit_ptr_hack.c */
--extern struct lineedit_statics *const lineedit_ptr_to_statics;
-+extern struct lineedit_statics * lineedit_ptr_to_statics;
- 
- #define S (*lineedit_ptr_to_statics)
- #define state            (S.state           )
---- a/shell/ash.c
-+++ b/shell/ash.c
-@@ -300,10 +300,9 @@ typedef long arith_t;
-  * set "-DBB_GLOBAL_CONST=''" in CONFIG_EXTRA_CFLAGS to disable
-  * this optimization.
-  */
--#ifndef BB_GLOBAL_CONST
--# define BB_GLOBAL_CONST const
--#endif
- 
-+#undef BB_GLOBAL_CONST
-+#define BB_GLOBAL_CONST
- 
- /* ============ Hash table sizes. Configurable. */
- 
diff --git a/recipes-core/busybox/busybox/0001-apply-const-trick-to-ptr_to_globals.patch b/recipes-core/busybox/busybox/0001-apply-const-trick-to-ptr_to_globals.patch
new file mode 100644
index 0000000..84b61a2
--- /dev/null
+++ b/recipes-core/busybox/busybox/0001-apply-const-trick-to-ptr_to_globals.patch
@@ -0,0 +1,48 @@
+From d3fbf09787b9dd8a061b541cd931ffbf63e4d610 Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Wed, 12 Jan 2022 10:48:36 -0800
+Subject: [PATCH] apply const trick to ptr_to_globals
+
+This was missing in the previous attempt to fix it via [1]
+
+This helps fix segfaults when compiling with clang ( seen on riscv64 )
+
+[  452.428349] less[270]: unhandled signal 11 code 0x1 at 0x000000000000000c in busybox.nosuid[2ab7491000+ba000]
+[  452.430246] CPU: 3 PID: 270 Comm: less Not tainted 5.15.13-yocto-standard #1
+[  452.431323] Hardware name: riscv-virtio,qemu (DT)
+[  452.431925] epc : 0000002ab74a19ee ra : 0000002ab74a19dc sp : 0000003fec6ec980
+[  452.432725]  gp : 0000002ab754dcb0 tp : 0000003f88783800 t0 : 0000003f8878d4a0
+[  452.433744]  t1 : 0000002ab749b00c t2 : 0000000000000000 s0 : 0000003fec6ecc38
+[  452.434732]  s1 : 000000000000004c a0 : 00000000ffffffff a1 : 0000002ab754dde0
+[  452.435861]  a2 : 0000000000000000 a3 : 0000000000000100 a4 : 0000002ab754f3a0
+[  452.436787]  a5 : 0000002ab754f3a0 a6 : 0000000000000000 a7 : 0000002ab754f2a0
+[  452.437974]  s2 : 0000000000000002 s3 : 0000002ab754b6c8 s4 : 0000002ab749b60e
+[  452.438781]  s5 : 0000000000000000 s6 : 0000002ab754b6c8 s7 : 0000003f88943060
+[  452.439723]  s8 : 0000003f88944050 s9 : 0000002ad8502e88 s10: 0000002ad8502de8
+[  452.440538]  s11: 0000000000000014 t3 : 0000003f887fceb6 t4 : 0000003f8893af0c
+[  452.441438]  t5 : 0000000000000000 t6 : 0000003f88923000
+
+[1] https://git.busybox.net/busybox/commit/?id=1f925038a
+
+Upstream-Status: Submitted [http://lists.busybox.net/pipermail/busybox/2022-January/089413.html]
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ include/libbb.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/include/libbb.h b/include/libbb.h
+index a487828..7b76335 100644
+--- a/include/libbb.h
++++ b/include/libbb.h
+@@ -2281,7 +2281,7 @@ struct globals;
+ /* '*const' ptr makes gcc optimize code much better.
+  * Magic prevents ptr_to_globals from going into rodata.
+  * If you want to assign a value, use SET_PTR_TO_GLOBALS(x) */
+-extern struct globals *const ptr_to_globals;
++extern struct globals *BB_GLOBAL_CONST ptr_to_globals;
+ 
+ #define barrier() asm volatile ("":::"memory")
+ 
+-- 
+2.34.1
+
diff --git a/recipes-core/busybox/busybox/clang.cfg b/recipes-core/busybox/busybox/clang.cfg
new file mode 100644
index 0000000..450fa7e
--- /dev/null
+++ b/recipes-core/busybox/busybox/clang.cfg
@@ -0,0 +1 @@
+CONFIG_EXTRA_CFLAGS="-DBB_GLOBAL_CONST=''"
diff --git a/recipes-core/busybox/busybox_1.34%.bbappend b/recipes-core/busybox/busybox_1.35%.bbappend
index 2c0af5e..fbe6279 100644
--- a/recipes-core/busybox/busybox_1.34%.bbappend
+++ b/recipes-core/busybox/busybox_1.35%.bbappend
@@ -1,7 +1,8 @@
 FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
+
 SRC_URI:append:toolchain-clang = "\
-    file://0001-Turn-ptr_to_globals-and-bb_errno-to-be-non-const.patch \
-"
+                                  file://0001-apply-const-trick-to-ptr_to_globals.patch \
+                                  file://clang.cfg"
 
 # networking/tls_pstm_sqr_comba.c:514:4: error: inline assembly requires more registers than available
 #                        SQRADD2(*tmpx++, *tmpy--);