mirror of
https://github.com/fluencelabs/musl
synced 2025-05-02 18:42:15 +00:00
e9e770dfd6
the entry point code supports being loaded by a loader which is not fdpic-aware (in practice, either kernel with mmu or qemu without fdpic support). this mostly just works, but signal handling will wrongly use a function descriptor address as a code address if the personality is not adjusted to fdpic. ideally this code could be placed with sigaction so that it's not needed except if/when a signal handler is installed. however, personality is incorrectly maintained per-thread by the kernel, rather than per-process, so it's necessary to correct the personality before any threads are started. also, in order to skip the personality syscall when an fdpic-aware loader is used, we need to be able to detect how the program was loaded, and this information is only readily available at the entry point.
72 lines
1.2 KiB
C
72 lines
1.2 KiB
C
#ifdef __SH_FDPIC__
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__asm__(
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".text \n"
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".global " START " \n"
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START ": \n"
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" tst r8, r8 \n"
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" bf 1f \n"
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" mov #68, r3 \n"
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" add r3, r3 \n"
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" mov #8, r4 \n"
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" swap.w r4, r4 \n"
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" trapa #31 \n"
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" nop \n"
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" nop \n"
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" nop \n"
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" nop \n"
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"1: nop \n"
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#ifndef SHARED
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" mov r8, r4 \n"
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" mova 1f, r0 \n"
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" mov.l 1f, r5 \n"
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" mov.l 1f+4, r6 \n"
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" add r0, r5 \n"
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" bsr __fdpic_fixup \n"
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" add r0, r6 \n"
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" mov r0, r12 \n"
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#endif
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" mov r10, r5 \n"
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" mov r15, r4 \n"
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" mov.l r9, @-r15 \n"
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" mov.l r8, @-r15 \n"
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" mov #-16, r0 \n"
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" bsr " START "_c \n"
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" and r0, r15 \n"
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".align 2 \n"
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"1: .long __ROFIXUP_LIST__@PCREL \n"
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" .long __ROFIXUP_END__@PCREL + 4 \n"
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);
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#ifndef SHARED
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#include "fdpic_crt.h"
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#endif
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#else
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__asm__(
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".text \n"
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".global " START " \n"
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START ": \n"
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" mova 1f, r0 \n"
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" mov.l 1f, r5 \n"
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" add r0, r5 \n"
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" mov r15, r4 \n"
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" mov #-16, r0 \n"
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" and r0, r15 \n"
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" bsr " START "_c \n"
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" nop \n"
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".align 2 \n"
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".weak _DYNAMIC \n"
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".hidden _DYNAMIC \n"
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"1: .long _DYNAMIC-. \n"
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);
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#endif
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/* used by gcc for switching the FPU between single and double precision */
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#ifdef SHARED
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__attribute__((__visibility__("hidden")))
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#endif
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const unsigned long __fpscr_values[2] = { 0, 0x80000 };
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