linux-kernel - [PATCH 2/2] riscv: Fixup static

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Date:   Wed,  7 Oct 2020 15:08:33 +0000
From:   guoren@...nel.org
To:     palmerdabbelt@...gle.com
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        atishp@...shpatra.org, schwab@...ux-m68k.org, aurelien@...el32.net,
        Guo Ren <guoren@...ux.alibaba.com>
Subject: [PATCH 2/2] riscv: Fixup static_obj() fail v2

From: Guo Ren <guoren@...ux.alibaba.com>

v1 is commit: 6184358da0004c8fd940afda6c0a0fa4027dc911 which has
been reverted.

When enable LOCKDEP, static_obj() will cause error:

[    0.067192] INFO: trying to register non-static key.
[    0.067325] the code is fine but needs lockdep annotation.
[    0.067449] turning off the locking correctness validator.
[    0.067718] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-rc7-dirty #44
[    0.067945] Call Trace:
[    0.068369] [<ffffffe00020323c>] walk_stackframe+0x0/0xa4
[    0.068506] [<ffffffe000203422>] show_stack+0x2a/0x34
[    0.068631] [<ffffffe000521e4e>] dump_stack+0x94/0xca
[    0.068757] [<ffffffe000255a4e>] register_lock_class+0x5b8/0x5bc
[    0.068969] [<ffffffe000255abe>] __lock_acquire+0x6c/0x1d5c
[    0.069101] [<ffffffe0002550fe>] lock_acquire+0xae/0x312
[    0.069228] [<ffffffe000989a8e>] _raw_spin_lock_irqsave+0x40/0x5a
[    0.069357] [<ffffffe000247c64>] complete+0x1e/0x50
[    0.069479] [<ffffffe000984c38>] rest_init+0x1b0/0x28a
[    0.069660] [<ffffffe0000016a2>] 0xffffffe0000016a2
[    0.069779] [<ffffffe000001b84>] 0xffffffe000001b84
[    0.069953] [<ffffffe000001092>] 0xffffffe000001092

Because some __initdata static variables is before _stext:

static int static_obj(const void *obj)
{
        unsigned long start = (unsigned long) &_stext,
                      end   = (unsigned long) &_end,
                      addr  = (unsigned long) obj;

        /*
         * static variable?
         */
        if ((addr >= start) && (addr < end))
                return 1;

	if (arch_is_kernel_data(addr))
		return 1;

We could implement arch_is_kernel_data to fixup it.

Link: https://lore.kernel.org/linux-riscv/1593266228-61125-1-git-send-email-guoren@kernel.org/T/#t
Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
Reported-by: Aurelien Jarno <aurelien@...el32.net>
Cc: Palmer Dabbelt <palmerdabbelt@...gle.com>
Cc: Atish Patra <atishp@...shpatra.org>
Cc: Andreas Schwab <schwab@...ux-m68k.org>
Cc: Aurelien Jarno <aurelien@...el32.net>
---
 arch/riscv/include/asm/sections.h | 20 ++++++++++++++++++++
 arch/riscv/kernel/setup.c         |  9 +++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 arch/riscv/include/asm/sections.h

diff --git a/arch/riscv/include/asm/sections.h b/arch/riscv/include/asm/sections.h
new file mode 100644
index 00000000..2317b9e
--- /dev/null
+++ b/arch/riscv/include/asm/sections.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_RISCV_SECTIONS_H
+#define _ASM_RISCV_SECTIONS_H
+
+#define arch_is_kernel_data arch_is_kernel_data
+
+#include <asm-generic/sections.h>
+
+extern bool init_mem_is_free;
+
+static inline int arch_is_kernel_data(unsigned long addr)
+{
+	if (init_mem_is_free)
+		return 0;
+
+	return addr >= (unsigned long)__init_begin &&
+		addr < (unsigned long)__init_end;
+}
+#endif /* _ASM_RISCV_SECTIONS_H */
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 2c6dd32..9ebd5eb4 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -17,6 +17,7 @@
 #include <linux/sched/task.h>
 #include <linux/swiotlb.h>
 #include <linux/smp.h>
+#include <linux/poison.h>
 
 #include <asm/cpu_ops.h>
 #include <asm/setup.h>
@@ -112,3 +113,11 @@ static int __init topology_init(void)
 	return 0;
 }
 subsys_initcall(topology_init);
+
+bool init_mem_is_free = false;
+
+void free_initmem(void)
+{
+	free_initmem_default(POISON_FREE_INITMEM);
+	init_mem_is_free = true;
+}
-- 
2.7.4