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Fixed MPIE being cleared leading to have interrupts being disable after an mret instruction #522

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Fixed MPIE being cleared leading to have interrupts being disable after an mret instruction #522

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29 changes: 12 additions & 17 deletions ports/risc-v64/gnu/src/tx_thread_context_restore.S
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Original file line number Diff line number Diff line change
Expand Up @@ -175,18 +175,11 @@ _tx_thread_context_restore:
Set MPIE and restore MPP to Machine, preserve other fields. */

csrr t1, mstatus
li t2, 0x1880 // Set MPP(0x1800) | MPIE(0x80)
li t3, ~0x8 // Preserve all bits except MIE

/* Clear MPP/MPIE/MIE bits in t1 then set desired values. */

li t2, 0x1888 // MPP(0x1800) | MPIE(0x80) | MIE(0x08)
li t3, 0x1800 // Set MPP to Machine mode (bits 12:11)

/* Construct new mstatus in t1: clear mask bits, set MPP/MPIE and optionally FP bit,
preserve everything except the bits we will modify. */

li t4, ~0x1888 // Clear mask for MPP/MPIE/MIE
and t1, t1, t4
or t1, t1, t3
or t1, t1, t2 // MPP and MPIE are now set
and t1, t1, t2 // Clear MIE, Hardware will restore it from MPIE

#if defined(__riscv_float_abi_single) || defined(__riscv_float_abi_double)
li t0, 0x2000 // Set FS bits (bits 14:13 to 01) for FP state
Expand Down Expand Up @@ -352,14 +345,16 @@ _tx_thread_no_preempt_restore:
ld t0, 30*8(sp) // Recover mepc
csrw mepc, t0 // Setup mepc

/* Compose mstatus via read/modify/write to avoid clobbering unrelated bits. */

/* Compose mstatus via read/modify/write to avoid clobbering unrelated bits.
Set MPIE and restore MPP to Machine, preserve other fields. */

csrr t1, mstatus
li t2, 0x1888 // MPP(0x1800) | MPIE(0x80) | MIE(0x08)
li t3, 0x1800 // Set MPP to Machine mode
li t4, ~0x1888 // Clear mask for MPP/MPIE/MIE
and t1, t1, t4
or t1, t1, t3
li t2, 0x1880 // Set MPP(0x1800) | MPIE(0x80)
li t3, ~0x8 // Preserve all bits except MIE

or t1, t1, t2 // MPP and MPIE are now set
and t1, t1, t2 // Clear MIE, Hardware will restore it from MPIE

#if defined(__riscv_float_abi_single) || defined(__riscv_float_abi_double)
li t0, 0x2000 // Set FS bits for FP state
Expand Down