From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, penberg@kernel.org,
geert@linux-m68k.org, rppt@kernel.org,
Giancarlo Ferrari <giancarlo.ferrari89@gmail.com>,
akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org,
giancarlo.ferrari@nokia.com
Subject: Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated
Date: Mon, 1 Feb 2021 13:03:45 +0000 [thread overview]
Message-ID: <20210201130344.GF1463@shell.armlinux.org.uk> (raw)
In-Reply-To: <20210201124720.GA66060@C02TD0UTHF1T.local>
On Mon, Feb 01, 2021 at 12:47:20PM +0000, Mark Rutland wrote:
> 1. copy reloc code into buffer
> 2. alter variables in copy of reloc code
> 3. branch to buffer
>
> ... which would avoid this class of problem too.
Yep, slightly messy to do though:
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 5d84ad333f05..6058e0d3a40d 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -174,18 +174,27 @@ void machine_kexec(struct kimage *image)
reboot_code_buffer = page_address(image->control_code_page);
- /* Prepare parameters for reboot_code_buffer*/
- set_kernel_text_rw();
- kexec_start_address = image->start;
- kexec_indirection_page = page_list;
- kexec_mach_type = machine_arch_type;
- kexec_boot_atags = image->arch.kernel_r2;
-
/* copy our kernel relocation code to the control code page */
reboot_entry = fncpy(reboot_code_buffer,
&relocate_new_kernel,
relocate_new_kernel_size);
+#define set(what, val) \
+ do { \
+ uintptr_t __funcp_address; \
+ int __offset; \
+ void *__ptr; \
+ asm("" : "=r" (__funcp_address) : "0" (&relocate_new_kernel)); \
+ __offset = (uintptr_t)&(what) - (__funcp_address & ~1); \
+ __ptr = reboot_code_buffer + __offset; \
+ *(__typeof__(&(what)))__ptr = val; \
+ } while (0)
+
+ set(kexec_start_address, image->start);
+ set(kexec_indirection_page, page_list);
+ set(kexec_mach_type, machine_arch_type);
+ set(kexec_boot_atags, image->arch.kernel_r2);
+
/* get the identity mapping physical address for the reboot code */
reboot_entry_phys = virt_to_idmap(reboot_entry);
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com>,
linux-kernel@vger.kernel.org, penberg@kernel.org,
geert@linux-m68k.org, linux-arm-kernel@lists.infradead.org,
akpm@linux-foundation.org, rppt@kernel.org,
giancarlo.ferrari@nokia.com
Subject: Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated
Date: Mon, 1 Feb 2021 13:03:45 +0000 [thread overview]
Message-ID: <20210201130344.GF1463@shell.armlinux.org.uk> (raw)
In-Reply-To: <20210201124720.GA66060@C02TD0UTHF1T.local>
On Mon, Feb 01, 2021 at 12:47:20PM +0000, Mark Rutland wrote:
> 1. copy reloc code into buffer
> 2. alter variables in copy of reloc code
> 3. branch to buffer
>
> ... which would avoid this class of problem too.
Yep, slightly messy to do though:
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 5d84ad333f05..6058e0d3a40d 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -174,18 +174,27 @@ void machine_kexec(struct kimage *image)
reboot_code_buffer = page_address(image->control_code_page);
- /* Prepare parameters for reboot_code_buffer*/
- set_kernel_text_rw();
- kexec_start_address = image->start;
- kexec_indirection_page = page_list;
- kexec_mach_type = machine_arch_type;
- kexec_boot_atags = image->arch.kernel_r2;
-
/* copy our kernel relocation code to the control code page */
reboot_entry = fncpy(reboot_code_buffer,
&relocate_new_kernel,
relocate_new_kernel_size);
+#define set(what, val) \
+ do { \
+ uintptr_t __funcp_address; \
+ int __offset; \
+ void *__ptr; \
+ asm("" : "=r" (__funcp_address) : "0" (&relocate_new_kernel)); \
+ __offset = (uintptr_t)&(what) - (__funcp_address & ~1); \
+ __ptr = reboot_code_buffer + __offset; \
+ *(__typeof__(&(what)))__ptr = val; \
+ } while (0)
+
+ set(kexec_start_address, image->start);
+ set(kexec_indirection_page, page_list);
+ set(kexec_mach_type, machine_arch_type);
+ set(kexec_boot_atags, image->arch.kernel_r2);
+
/* get the identity mapping physical address for the reboot code */
reboot_entry_phys = virt_to_idmap(reboot_entry);
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2021-02-01 13:05 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-01 0:44 [PATCH] ARM: kexec: Fix panic after TLB are invalidated Giancarlo Ferrari
2021-02-01 0:44 ` Giancarlo Ferrari
2021-02-01 11:34 ` Russell King - ARM Linux admin
2021-02-01 11:34 ` Russell King - ARM Linux admin
2021-02-01 12:47 ` Mark Rutland
2021-02-01 12:47 ` Mark Rutland
2021-02-01 13:03 ` Russell King - ARM Linux admin [this message]
2021-02-01 13:03 ` Russell King - ARM Linux admin
2021-02-01 13:57 ` Mark Rutland
2021-02-01 13:57 ` Mark Rutland
2021-02-01 16:08 ` Russell King - ARM Linux admin
2021-02-01 16:08 ` Russell King - ARM Linux admin
2021-02-01 16:32 ` Mark Rutland
2021-02-01 16:32 ` Mark Rutland
2021-02-01 16:37 ` Russell King - ARM Linux admin
2021-02-01 16:37 ` Russell King - ARM Linux admin
2021-02-01 20:07 ` Giancarlo Ferrari
2021-02-01 20:07 ` Giancarlo Ferrari
2021-02-01 20:16 ` Russell King - ARM Linux admin
2021-02-01 20:16 ` Russell King - ARM Linux admin
2021-02-01 22:18 ` Giancarlo Ferrari
2021-02-01 22:18 ` Giancarlo Ferrari
2021-02-04 23:48 ` Giancarlo Ferrari
2021-02-04 23:48 ` Giancarlo Ferrari
2021-02-05 0:18 ` Russell King - ARM Linux admin
2021-02-05 0:18 ` Russell King - ARM Linux admin
2021-02-05 0:40 ` Giancarlo Ferrari
2021-02-05 0:40 ` Giancarlo Ferrari
2021-02-05 0:45 ` Giancarlo Ferrari
2021-02-05 0:45 ` Giancarlo Ferrari
2021-02-05 9:44 ` Russell King - ARM Linux admin
2021-02-05 9:44 ` Russell King - ARM Linux admin
2021-02-05 14:36 ` Giancarlo Ferrari
2021-02-05 14:36 ` Giancarlo Ferrari
2021-02-01 14:39 ` Giancarlo Ferrari
2021-02-01 14:39 ` Giancarlo Ferrari
2021-02-01 15:30 ` Mark Rutland
2021-02-01 15:30 ` Mark Rutland
2021-02-01 19:09 ` Giancarlo Ferrari
2021-02-01 19:09 ` Giancarlo Ferrari
-- strict thread matches above, loose matches on Subject: below --
2021-01-12 16:49 Giancarlo Ferrari
2021-01-12 16:49 ` Giancarlo Ferrari
2021-02-01 10:10 ` Giancarlo Ferrari
2021-02-01 10:10 ` Giancarlo Ferrari
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