linux-kernel - Re: [PATCH v3] riscv: make sure the cores stay looping in .Lsecondary

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Date:   Thu, 9 Jan 2020 11:27:34 -0800 (PST)
From:   Paul Walmsley <paul.walmsley@...ive.com>
To:     Greentime Hu <greentime.hu@...ive.com>
cc:     green.hu@...il.com, greentime@...nel.org, palmer@...belt.com,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        schwab@...e.de, anup@...infault.org
Subject: Re: [PATCH v3] riscv: make sure the cores stay looping in
 .Lsecondary_park

On Thu, 9 Jan 2020, Greentime Hu wrote:

> The code in secondary_park is currently placed in the .init section.  The
> kernel reclaims and clears this code when it finishes booting.  That
> causes the cores parked in it to go to somewhere unpredictable, so we
> move this function out of init to make sure the cores stay looping there.
> 
> Signed-off-by: Greentime Hu <greentime.hu@...ive.com>
> Reviewed-by: Anup Patel <anup@...infault.org>

Thanks, the following is what's been queued for v5.5-rc.


- Paul

From: Greentime Hu <greentime.hu@...ive.com>
Date: Thu, 9 Jan 2020 11:15:16 +0800
Subject: [PATCH] riscv: make sure the cores stay looping in .Lsecondary_park

The code in secondary_park is currently placed in the .init section.  The
kernel reclaims and clears this code when it finishes booting.  That
causes the cores parked in it to go to somewhere unpredictable, so we
move this function out of init to make sure the cores stay looping there.

Signed-off-by: Greentime Hu <greentime.hu@...ive.com>
Reviewed-by: Anup Patel <anup@...infault.org>
Cc: Andreas Schwab <schwab@...e.de>
Cc: stable@...r.kernel.org
Fixes: 76d2a0493a17d ("RISC-V: Init and Halt Code")
Signed-off-by: Paul Walmsley <paul.walmsley@...ive.com>
---
 arch/riscv/kernel/head.S | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 797802c73dee..c9cc44ef7184 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -209,11 +209,6 @@ relocate:
 	tail smp_callin
 #endif
 
-.align 2
-.Lsecondary_park:
-	/* We lack SMP support or have too many harts, so park this hart */
-	wfi
-	j .Lsecondary_park
 END(_start)
 
 #ifdef CONFIG_RISCV_M_MODE
@@ -295,6 +290,13 @@ ENTRY(reset_regs)
 END(reset_regs)
 #endif /* CONFIG_RISCV_M_MODE */
 
+.section ".text", "ax",@progbits
+.align 2
+.Lsecondary_park:
+	/* We lack SMP support or have too many harts, so park this hart */
+	wfi
+	j .Lsecondary_park
+
 __PAGE_ALIGNED_BSS
 	/* Empty zero page */
 	.balign PAGE_SIZE
-- 
2.25.0.rc2