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riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT
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Lockdep is needed by proving the spinlocks and rwlocks. To suupport
it, we need fixup TRACE_IRQFLAGS_SUPPORT in kernel/entry.S. This
patch follow Documentation/irqflags-tracing.txt.

Signed-off-by: Guo Ren <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>
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guoren83 authored and palmer-dabbelt committed Jul 30, 2020
1 parent c159599 commit 3c46979
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Showing 2 changed files with 36 additions and 1 deletion.
3 changes: 3 additions & 0 deletions arch/riscv/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -179,6 +179,9 @@ config PGTABLE_LEVELS
default 3 if 64BIT
default 2

config LOCKDEP_SUPPORT
def_bool y

source "arch/riscv/Kconfig.socs"

menu "Platform type"
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34 changes: 33 additions & 1 deletion arch/riscv/kernel/entry.S
Original file line number Diff line number Diff line change
Expand Up @@ -97,19 +97,26 @@ _save_context:
la gp, __global_pointer$
.option pop

la ra, ret_from_exception
#ifdef CONFIG_TRACE_IRQFLAGS
call trace_hardirqs_off
#endif
/*
* MSB of cause differentiates between
* interrupts and exceptions
*/
bge s4, zero, 1f

la ra, ret_from_exception

/* Handle interrupts */
move a0, sp /* pt_regs */
la a1, handle_arch_irq
REG_L a1, (a1)
jr a1
1:
#ifdef CONFIG_TRACE_IRQFLAGS
call trace_hardirqs_on
#endif
/*
* Exceptions run with interrupts enabled or disabled depending on the
* state of SR_PIE in m/sstatus.
Expand All @@ -119,6 +126,7 @@ _save_context:
csrs CSR_STATUS, SR_IE

1:
la ra, ret_from_exception
/* Handle syscalls */
li t0, EXC_SYSCALL
beq s4, t0, handle_syscall
Expand All @@ -137,6 +145,17 @@ _save_context:
tail do_trap_unknown

handle_syscall:
#ifdef CONFIG_TRACE_IRQFLAGS
/* Recover a0 - a7 for system calls */
REG_L a0, PT_A0(sp)
REG_L a1, PT_A1(sp)
REG_L a2, PT_A2(sp)
REG_L a3, PT_A3(sp)
REG_L a4, PT_A4(sp)
REG_L a5, PT_A5(sp)
REG_L a6, PT_A6(sp)
REG_L a7, PT_A7(sp)
#endif
/* save the initial A0 value (needed in signal handlers) */
REG_S a0, PT_ORIG_A0(sp)
/*
Expand Down Expand Up @@ -190,6 +209,9 @@ ret_from_syscall_rejected:
ret_from_exception:
REG_L s0, PT_STATUS(sp)
csrc CSR_STATUS, SR_IE
#ifdef CONFIG_TRACE_IRQFLAGS
call trace_hardirqs_off
#endif
#ifdef CONFIG_RISCV_M_MODE
/* the MPP value is too large to be used as an immediate arg for addi */
li t0, SR_MPP
Expand All @@ -216,6 +238,16 @@ resume_userspace:
csrw CSR_SCRATCH, tp

restore_all:
#ifdef CONFIG_TRACE_IRQFLAGS
REG_L s1, PT_STATUS(sp)
andi t0, s1, SR_PIE
beqz t0, 1f
call trace_hardirqs_on
j 2f
1:
call trace_hardirqs_off
2:
#endif
REG_L a0, PT_STATUS(sp)
/*
* The current load reservation is effectively part of the processor's
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