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std: Slim down the error code path in initStaticTLS #6735

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Merged
andrewrk merged 1 commit into from
Oct 22, 2020
Merged

std: Slim down the error code path in initStaticTLS #6735

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16 changes: 10 additions & 6 deletions lib/std/os/linux/tls.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -211,12 +211,16 @@ fn initTLS() void {
}
}

// If the cpu is ARM-based, check if it supports the TLS register
if (comptime builtin.arch.isARM() and at_hwcap & std.os.linux.HWCAP_TLS == 0) {
// If the CPU does not support TLS via a coprocessor register,
// a kernel helper function can be used instead on certain linux kernels.
// See linux/arch/arm/include/asm/tls.h and musl/src/thread/arm/__set_thread_area.c.
@panic("TODO: Implement ARM fallback TLS functionality");
// ARMv6 targets (and earlier) have no support for TLS in hardware
// FIXME: Elide the check for targets >= ARMv7 when the target feature API
// becomes less verbose (and more usable).
if (comptime builtin.arch.isARM()) {
if (at_hwcap & std.os.linux.HWCAP_TLS == 0) {
// FIXME: Make __aeabi_read_tp call the kernel helper kuser_get_tls
// For the time being use a simple abort instead of a @panic call to
// keep the binary bloat under control.
std.os.abort();
}
}

var tls_align_factor: usize = undefined;
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