unwind-libdw.c

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// SPDX-License-Identifier: GPL-2.0
#include <elfutils/libdwfl.h>
#include "../../util/unwind-libdw.h"
#include "../../util/perf_regs.h"
#include "../../util/event.h"

bool libdw__arch_set_initial_registers(Dwfl_Thread *thread, void *arg)
{
    struct unwind_info *ui = arg;
    struct regs_dump *user_regs = &ui->sample->user_regs;
    Dwarf_Word dwarf_regs[17];
    unsigned nregs;

#define REG(r) ({                       \
    Dwarf_Word val = 0;                 \
    perf_reg_value(&val, user_regs, PERF_REG_X86_##r);  \
    val;                            \
})

    if (user_regs->abi == PERF_SAMPLE_REGS_ABI_32) {
        dwarf_regs[0] = REG(AX);
        dwarf_regs[1] = REG(CX);
        dwarf_regs[2] = REG(DX);
        dwarf_regs[3] = REG(BX);
        dwarf_regs[4] = REG(SP);
        dwarf_regs[5] = REG(BP);
        dwarf_regs[6] = REG(SI);
        dwarf_regs[7] = REG(DI);
        dwarf_regs[8] = REG(IP);
        nregs = 9;
    } else {
        dwarf_regs[0]  = REG(AX);
        dwarf_regs[1]  = REG(DX);
        dwarf_regs[2]  = REG(CX);
        dwarf_regs[3]  = REG(BX);
        dwarf_regs[4]  = REG(SI);
        dwarf_regs[5]  = REG(DI);
        dwarf_regs[6]  = REG(BP);
        dwarf_regs[7]  = REG(SP);
        dwarf_regs[8]  = REG(R8);
        dwarf_regs[9]  = REG(R9);
        dwarf_regs[10] = REG(R10);
        dwarf_regs[11] = REG(R11);
        dwarf_regs[12] = REG(R12);
        dwarf_regs[13] = REG(R13);
        dwarf_regs[14] = REG(R14);
        dwarf_regs[15] = REG(R15);
        dwarf_regs[16] = REG(IP);
        nregs = 17;
    }

    return dwfl_thread_state_registers(thread, 0, nregs, dwarf_regs);
}