From 6f45b39e4dbabf0b179a60ffacf434e55b2d5eab Mon Sep 17 00:00:00 2001 From: Joel Sing Date: Tue, 19 May 2020 18:55:31 +1000 Subject: cmd/compile,cmd/internal/obj/riscv: move g register on riscv64 The original riscv64 port used the thread pointer (TP aka X4) register for the g pointer, however this register is also used when TLS support is required, resulting in a conflict (for example, when a signal is received we have no way of readily knowing if X4 contains a pointer to the TCB or a pointer to a g). In order to support cgo, free up the X4 register by moving g to X27. This unfortunately means that the X4 register is unused in non-cgo mode, however the alternative is to not support cgo on this platform. Update #36641 Change-Id: Idcaf3e8ccbe42972a1b8943aeefde7149d9c960a Reviewed-on: https://go-review.googlesource.com/c/go/+/263477 Trust: Joel Sing Reviewed-by: Cherry Zhang --- src/cmd/internal/obj/riscv/cpu.go | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'src/cmd/internal/obj/riscv/cpu.go') diff --git a/src/cmd/internal/obj/riscv/cpu.go b/src/cmd/internal/obj/riscv/cpu.go index 482f9e0b6d..b1324b62a0 100644 --- a/src/cmd/internal/obj/riscv/cpu.go +++ b/src/cmd/internal/obj/riscv/cpu.go @@ -109,7 +109,7 @@ const ( REG_RA = REG_X1 // aka REG_LR REG_SP = REG_X2 REG_GP = REG_X3 // aka REG_SB - REG_TP = REG_X4 // aka REG_G + REG_TP = REG_X4 REG_T0 = REG_X5 REG_T1 = REG_X6 REG_T2 = REG_X7 @@ -132,17 +132,17 @@ const ( REG_S8 = REG_X24 REG_S9 = REG_X25 REG_S10 = REG_X26 - REG_S11 = REG_X27 + REG_S11 = REG_X27 // aka REG_G REG_T3 = REG_X28 REG_T4 = REG_X29 REG_T5 = REG_X30 REG_T6 = REG_X31 // aka REG_TMP // Go runtime register names. - REG_G = REG_TP // G pointer. - REG_CTXT = REG_S4 // Context for closures. - REG_LR = REG_RA // Link register. - REG_TMP = REG_T6 // Reserved for assembler use. + REG_G = REG_S11 // G pointer. + REG_CTXT = REG_S4 // Context for closures. + REG_LR = REG_RA // Link register. + REG_TMP = REG_T6 // Reserved for assembler use. // ABI names for floating point registers. REG_FT0 = REG_F0 -- cgit v1.3