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Message-ID: <alpine.DEB.2.11.1510112115190.6097@nanos>
Date: Sun, 11 Oct 2015 21:18:21 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
cc: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, x86@...nel.org
Subject: Re: [PATCH v2 1/1] x86/early_printk: Use __iomem address space for
IO
Andy,
On Fri, 9 Oct 2015, Andy Shevchenko wrote:
> #ifdef CONFIG_PCI
> static void mem32_serial_out(unsigned long addr, int offset, int value)
> {
> - u32 *vaddr = (u32 *)addr;
> + void __iomem *vaddr = (void __iomem *)addr;
> /* shift implied by pointer type */
> writel(value, vaddr + offset);
This is broken. Assume vaddr = 0x1000 and offset = 1
==> u32 *vaddr = 0x1000;
==> vaddr + offset = 0x1004
with your change
==> void __iomem *vaddr = 0x1000;
==> vaddr + offset = 0x1001
This comment is there for a reason:
> /* shift implied by pointer type */
Thanks,
tglx
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