linux-kernel - Re: [PATCH] riscv: change CSR M/S defines to use "X" for prefix

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Date:   Fri, 3 Jan 2020 17:28:44 -0800 (PST)
From:   Paul Walmsley <paul.walmsley@...ive.com>
To:     Olof Johansson <olof@...om.net>
cc:     Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Thomas Gleixner <tglx@...utronix.de>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        jason@...edaemon.net, maz@...nel.org, damien.lemoal@....com,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH] riscv: change CSR M/S defines to use "X" for prefix

On Wed, 18 Dec 2019, Olof Johansson wrote:

> Commit a4c3733d32a7 ("riscv: abstract out CSR names for supervisor vs
> machine mode") introduced new non-S/M-specific defines for some of the
> CSRs and fields that differ for when you run the kernel in machine or
> supervisor mode.
> 
> One of those was "IRQ_TIMER" (instead of IRQ_S_TIMER/IRQ_M_MTIMER),
> which was generic enough to cause conflicts with other defines in
> drivers. Since it was in csr.h, it ended up getting pulled in through
> fairly generic include files, etc.
> 
> I looked at just renaming those, but for consistency I chose to rename all
> M/S symbols to using 'X' instead of 'S'/'M' in the identifiers instead,
> which gives them all less generic names.
> 
> This is pretty churny, and I'm sure there'll be opinions on naming, but
> I figured I'd do the busywork of fixing it up instead of just pointing
> out the conflicts.
> 
> Fixes: a4c3733d32a7 ("riscv: abstract out CSR names for supervisor vs machine mode")
> Cc: Christoph Hellwig <hch@....de>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Olof Johansson <olof@...om.net>

Thanks for taking a stab at fixing the issue.  I queued the following 
minimal fix has been queued for v5.5-rc, adding an RV_ prefix to the IRQ_* 
macros.  It may be that we need to do the same thing to the rest of the 
CSRs.  But, based on a quick look, I think we should be OK for the moment.  
Let us know if you have a different point of view.


- Paul

From: Paul Walmsley <paul.walmsley@...ive.com>
Date: Fri, 20 Dec 2019 03:09:49 -0800
Subject: [PATCH] riscv: prefix IRQ_ macro names with an RV_ namespace

"IRQ_TIMER", used in the arch/riscv CSR header file, is a sufficiently
generic macro name that it's used by several source files across the
Linux code base.  Some of these other files ultimately include the
arch/riscv CSR include file, causing collisions.  Fix by prefixing the
RISC-V csr.h IRQ_ macro names with an RV_ prefix.

Fixes: a4c3733d32a72 ("riscv: abstract out CSR names for supervisor vs machine mode")
Reported-by: Olof Johansson <olof@...om.net>
Signed-off-by: Paul Walmsley <paul.walmsley@...ive.com>
---
 arch/riscv/include/asm/csr.h      | 18 +++++++++---------
 arch/riscv/kernel/irq.c           |  6 +++---
 drivers/irqchip/irq-sifive-plic.c |  2 +-
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 0a62d2d68455..435b65532e29 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -116,9 +116,9 @@
 # define SR_PIE		SR_MPIE
 # define SR_PP		SR_MPP
 
-# define IRQ_SOFT	IRQ_M_SOFT
-# define IRQ_TIMER	IRQ_M_TIMER
-# define IRQ_EXT	IRQ_M_EXT
+# define RV_IRQ_SOFT		IRQ_M_SOFT
+# define RV_IRQ_TIMER	IRQ_M_TIMER
+# define RV_IRQ_EXT		IRQ_M_EXT
 #else /* CONFIG_RISCV_M_MODE */
 # define CSR_STATUS	CSR_SSTATUS
 # define CSR_IE		CSR_SIE
@@ -133,15 +133,15 @@
 # define SR_PIE		SR_SPIE
 # define SR_PP		SR_SPP
 
-# define IRQ_SOFT	IRQ_S_SOFT
-# define IRQ_TIMER	IRQ_S_TIMER
-# define IRQ_EXT	IRQ_S_EXT
+# define RV_IRQ_SOFT		IRQ_S_SOFT
+# define RV_IRQ_TIMER	IRQ_S_TIMER
+# define RV_IRQ_EXT		IRQ_S_EXT
 #endif /* CONFIG_RISCV_M_MODE */
 
 /* IE/IP (Supervisor/Machine Interrupt Enable/Pending) flags */
-#define IE_SIE		(_AC(0x1, UL) << IRQ_SOFT)
-#define IE_TIE		(_AC(0x1, UL) << IRQ_TIMER)
-#define IE_EIE		(_AC(0x1, UL) << IRQ_EXT)
+#define IE_SIE		(_AC(0x1, UL) << RV_IRQ_SOFT)
+#define IE_TIE		(_AC(0x1, UL) << RV_IRQ_TIMER)
+#define IE_EIE		(_AC(0x1, UL) << RV_IRQ_EXT)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 3f07a91d5afb..345c4f2eba13 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -23,11 +23,11 @@ asmlinkage __visible void __irq_entry do_IRQ(struct pt_regs *regs)
 
 	irq_enter();
 	switch (regs->cause & ~CAUSE_IRQ_FLAG) {
-	case IRQ_TIMER:
+	case RV_IRQ_TIMER:
 		riscv_timer_interrupt();
 		break;
 #ifdef CONFIG_SMP
-	case IRQ_SOFT:
+	case RV_IRQ_SOFT:
 		/*
 		 * We only use software interrupts to pass IPIs, so if a non-SMP
 		 * system gets one, then we don't know what to do.
@@ -35,7 +35,7 @@ asmlinkage __visible void __irq_entry do_IRQ(struct pt_regs *regs)
 		riscv_software_interrupt();
 		break;
 #endif
-	case IRQ_EXT:
+	case RV_IRQ_EXT:
 		handle_arch_irq(regs);
 		break;
 	default:
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 8df547d2d935..0aca5807a119 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -256,7 +256,7 @@ static int __init plic_init(struct device_node *node,
 		 * Skip contexts other than external interrupts for our
 		 * privilege level.
 		 */
-		if (parent.args[0] != IRQ_EXT)
+		if (parent.args[0] != RV_IRQ_EXT)
 			continue;
 
 		hartid = plic_find_hart_id(parent.np);
-- 
2.24.0