Commit graph

9 commits

Author SHA1 Message Date
Elliott Hughes
b692ecb913 ELS TLS documentation: s/module/module_id/.
The field is actually called `module_id` in the code.

Test: N/A
Change-Id: I10f5ce07cb67f7f338036c49e0008c3dce2db0bd
2023-04-03 14:31:37 +00:00
Elliott Hughes
3e4f603c7f riscv64: build the linker.
The only meaningful change from alibaba's version is jr instead of jalr.

Also fix the comment that's in all the begin.S files while we're here.

Signed-off-by: Mao Han <han_mao@linux.alibaba.com>
Signed-off-by: Xia Lifang <lifang_xia@linux.alibaba.com>
Signed-off-by: Chen Guoyin <chenguoyin.cgy@linux.alibaba.com>
Signed-off-by: Wang Chen <wangchen20@iscas.ac.cn>
Signed-off-by: Lu Xufan <luxufan@iscas.ac.cn>
Test: ran mksh
Change-Id: I2645c78bd700b8a55bde363600d7f8b87de641a1
2022-10-22 03:57:11 +00:00
Colin Cross
a0a591a714 Don't use prefix_symbols for host bionic linker wrapper
The only symbol that actually needs a prefix to avoid a collision is
_start, and that can be handled with a copy of begin.S that uses a
"#define" to rename _start to __dlwrap__start. Removing the prefixed
symbols will also allow simplifying the host bionic build process by
letting it directly reference the real _start.

Test: build and run host bionic binary
Change-Id: I50be786c16fe04b7f05c14ebfb74f710c7446ed9
2021-06-14 12:24:25 -07:00
Christopher Ferris
c5d3a4348a Make tls related header files platform accessible.
There are places in frameworks and art code that directly included
private bionic header files. Move these files to the new platform
include files.

This change also moves the __get_tls.h header file to tls.h and includes
the tls defines header so that there is a single header that platform
code can use to get __get_tls and the defines.

Also, simplify the visibility rules for platform includes.

Bug: 141560639

Test: Builds and bionic unit tests pass.
Change-Id: I9e5e9c33fe8a85260f69823468bc9d340ab7a1f9
Merged-In: I9e5e9c33fe8a85260f69823468bc9d340ab7a1f9
(cherry picked from commit 44631c919a)
2019-09-27 12:14:24 -07:00
Ryan Prichard
ffaae70936 Implement arm64 TLSDESC
Each TLSDESC relocation relocates a 2-word descriptor in the GOT that
contains:
 - the address of a TLS resolver function
 - an argument to pass (indirectly) to the resolver function

(Specifically, the address of the 2-word descriptor is passed to the
resolver.)

The loader resolves R_GENERIC_TLSDESC relocations using one of three
resolver functions that it defines:
 - tlsdesc_resolver_static
 - tlsdesc_resolver_dynamic
 - tlsdesc_resolver_unresolved_weak

The resolver functions are written in assembly because they have a
restrictive calling convention. They're only allowed to modify x0 and
(apparently) the condition codes.

For a relocation to memory in static TLS (i.e. the executable or an solib
loaded initially), the loader uses a simple resolver function,
tlsdesc_resolver_static, that returns the static offset it receives from
the loader.

For relocations to dynamic TLS memory (i.e. memory in a dlopen'ed solib),
the loader uses tlsdesc_resolver_dynamic, which allocates TLS memory on
demand. It inlines the fast path of __tls_get_addr, then falls back to
__tls_get_addr when it needs to allocate memory. The loader handles these
dynamic TLS relocations in two passes:
 - In the first pass, it allocates a table of TlsDynamicResolverArg
   objects, one per dynamic TLSDESC relocation.
 - In the second pass, once the table is finalized, it writes the
   addresses of the TlsDynamicResolverArg objects into the TLSDESC
   relocations.

tlsdesc_resolver_unresolved_weak returns a negated thread pointer so that
taking the address of an unresolved weak TLS symbols produces NULL.

The loader handles R_GENERIC_TLSDESC in a target-independent way, but
only for arm64, because Bionic has only implemented the resolver functions
for arm64.

Bug: http://b/78026329
Test: bionic unit tests
Test: check that backtrace works inside a resolver function and inside
  __tls_get_addr called from a resolver
  (gdbclient.py, b __tls_get_addr, bt)
Merged-In: I752e59ff986292449892c449dad2546e6f0ff7b6
Change-Id: I752e59ff986292449892c449dad2546e6f0ff7b6
2019-01-29 08:33:09 +00:00
Christopher Ferris
aa81761c5e Force _start to be the top frame for the linker.
I noticed that sometimes the old unwinder will add an extra PC 0 frame
after this change, but the new unwinder works in all cases. I'm not going
to fix the old unwinder since I plan to remove it very soon.

Bug: 67784501

Test: Forced a crash in the linker and verified that the unwind
Test: stops in __dl_start. Tested on arm/aarch64/x86/x86_64.

Change-Id: Id6585768023256be5c1d341df7b06b786a220b40
2017-10-16 14:43:34 -07:00
Elliott Hughes
996524383f Don't zero r1 on entry to the dynamic linker.
There's no need: __linker_init only takes one argument.

Also remove the arm __CTOR_LIST__; we use .init_array and .fini_array instead
of .ctor and .dtor anyway, and I don't think we've ever supported the latter.

Change-Id: Ifc91a5a90c6aa39d674bf0509a7af2e1ff0beddd
2014-07-08 21:38:32 -07:00
Elliott Hughes
851e68a240 Unify our assembler macros.
Our <machine/asm.h> files were modified from upstream, to the extent
that no architecture was actually using the upstream ENTRY or END macros,
assuming that architecture even had such a macro upstream. This patch moves
everyone to the same macros, with just a few tweaks remaining in the
<machine/asm.h> files, which no one should now use directly.

I've removed most of the unused cruft from the <machine/asm.h> files, though
there's still rather a lot in the mips/mips64 ones.

Bug: 12229603
Change-Id: I2fff287dc571ac1087abe9070362fb9420d85d6d
2014-02-20 13:51:26 -08:00
Colin Cross
d1973ca513 bionic: rename aarch64 target to arm64
Rename aarch64 build targets to arm64.  The gcc toolchain is still
aarch64.

Change-Id: Ia92d8a50824e5329cf00fd6f4f92eae112b7f3a3
2014-01-23 18:35:39 -08:00