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x86-64: Handle fewer relocation types for RTLD_BOOTSTRAP

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The RTLD_BOOTSTRAP branch is used to relocate ld.so itself.  It only
needs to handle RELATIVE, GLOB_DAT, and JUMP_SLOT.  RELATIVE has been
handled (by _ELF_DYNAMIC_DO_RELOC due to DT_RELACOUNT, or RELR), so the
switch statement only needs to handle GLOB_DAT and JUMP_SLOT.

We can drop these `#if[n]def RTLD_BOOTSTRAP` and add a large
`# ifndef RTLD_BOOTSTRAP` instead.
This commit is contained in:
Fangrui Song 2022-06-16 11:48:15 -07:00
parent e89913d0aa
commit 4ef05df5ef
1 changed files with 6 additions and 26 deletions
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32
sysdeps/x86_64/dl-machine.h
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@ -298,6 +298,11 @@ and creates an unsatisfiable circular dependency.\n",
switch (r_type)
{
case R_X86_64_GLOB_DAT:
case R_X86_64_JUMP_SLOT:
*reloc_addr = value;
break;
# ifndef RTLD_BOOTSTRAP
# ifdef __ILP32__
case R_X86_64_SIZE64:
@ -314,29 +319,14 @@ and creates an unsatisfiable circular dependency.\n",
value = sym->st_size;
*reloc_addr = value + reloc->r_addend;
break;
# endif
case R_X86_64_GLOB_DAT:
case R_X86_64_JUMP_SLOT:
*reloc_addr = value;
break;
case R_X86_64_DTPMOD64:
# ifdef RTLD_BOOTSTRAP
/* During startup the dynamic linker is always the module
with index 1.
XXX If this relocation is necessary move before RESOLVE
call. */
*reloc_addr = 1;
# else
/* Get the information from the link map returned by the
resolve function. */
if (sym_map != NULL)
*reloc_addr = sym_map->l_tls_modid;
# endif
break;
case R_X86_64_DTPOFF64:
# ifndef RTLD_BOOTSTRAP
/* During relocation all TLS symbols are defined and used.
Therefore the offset is already correct. */
if (sym != NULL)
@ -353,23 +343,19 @@ and creates an unsatisfiable circular dependency.\n",
*reloc_addr = value;
# endif
}
# endif
break;
case R_X86_64_TLSDESC:
{
struct tlsdesc volatile *td =
(struct tlsdesc volatile *)reloc_addr;
# ifndef RTLD_BOOTSTRAP
if (! sym)
{
td->arg = (void*)reloc->r_addend;
td->entry = _dl_tlsdesc_undefweak;
}
else
# endif
{
# ifndef RTLD_BOOTSTRAP
# ifndef SHARED
CHECK_STATIC_TLS (map, sym_map);
# else
@ -381,7 +367,6 @@ and creates an unsatisfiable circular dependency.\n",
}
else
# endif
# endif
{
td->arg = (void*)(sym->st_value - sym_map->l_tls_offset
+ reloc->r_addend);
@ -392,13 +377,9 @@ and creates an unsatisfiable circular dependency.\n",
}
case R_X86_64_TPOFF64:
/* The offset is negative, forward from the thread pointer. */
# ifndef RTLD_BOOTSTRAP
if (sym != NULL)
# endif
{
# ifndef RTLD_BOOTSTRAP
CHECK_STATIC_TLS (map, sym_map);
# endif
/* We know the offset of the object the symbol is contained in.
It is a negative value which will be added to the
thread pointer. */
@ -416,7 +397,6 @@ and creates an unsatisfiable circular dependency.\n",
}
break;
# ifndef RTLD_BOOTSTRAP
case R_X86_64_64:
/* value + r_addend may be > 0xffffffff and R_X86_64_64
relocation updates the whole 64-bit entry. */
@ -481,7 +461,7 @@ and creates an unsatisfiable circular dependency.\n",
default:
_dl_reloc_bad_type (map, r_type, 0);
break;
# endif
# endif /* !RTLD_BOOTSTRAP */
}
}
}