linux-kernel - Re: [PATCH 4.9 111/111] MIPS: VDSO: Drop gic_get_usm

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Date:   Mon, 24 Sep 2018 18:35:48 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Paul Burton <paul.burton@...tec.com>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-mips@...ux-mips.org, Ralf Baechle <ralf@...ux-mips.org>,
        SZ Lin <sz.lin@...a.com>
Subject: Re: [PATCH 4.9 111/111] MIPS: VDSO: Drop gic_get_usm_range() usage

On Mon, Sep 24, 2018 at 01:53:18PM +0200, Greg Kroah-Hartman wrote:
> 4.9-stable review patch.  If anyone has any objections, please let me know.
> 

This patch breaks v4.4.y and v4.9.y builds.
It includes asm/mips-cps.h which doesn't exist in those releases.

Building mips:malta_defconfig:smp:initrd ... failed
------------
Error log:
arch/mips/kernel/vdso.c:23:26: fatal error: asm/mips-cps.h: No such file or directory

Guenter

> ------------------
> 
> From: Paul Burton <paul.burton@...tec.com>
> 
> commit 00578cd864d45ae4b8fa3f684f8d6f783dd8d15d upstream.
> 
> We don't really need gic_get_usm_range() to abstract discovery of the
> address of the GIC user-visible section now that we have access to its
> base address globally.
> 
> Switch to calculating it ourselves, which will allow us to stop
> requiring the irqchip driver to care about a counter exposed to userland
> for use via the VDSO.
> 
> Signed-off-by: Paul Burton <paul.burton@...tec.com>
> Cc: Jason Cooper <jason@...edaemon.net>
> Cc: Marc Zyngier <marc.zyngier@....com>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: linux-mips@...ux-mips.org
> Patchwork: https://patchwork.linux-mips.org/patch/17040/
> Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
> Signed-off-by: SZ Lin (林上智) <sz.lin@...a.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> ---
>  arch/mips/kernel/vdso.c |   15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> --- a/arch/mips/kernel/vdso.c
> +++ b/arch/mips/kernel/vdso.c
> @@ -13,7 +13,6 @@
>  #include <linux/err.h>
>  #include <linux/init.h>
>  #include <linux/ioport.h>
> -#include <linux/irqchip/mips-gic.h>
>  #include <linux/kernel.h>
>  #include <linux/mm.h>
>  #include <linux/sched.h>
> @@ -21,6 +20,7 @@
>  #include <linux/timekeeper_internal.h>
>  
>  #include <asm/abi.h>
> +#include <asm/mips-cps.h>
>  #include <asm/page.h>
>  #include <asm/vdso.h>
>  
> @@ -101,9 +101,8 @@ int arch_setup_additional_pages(struct l
>  {
>  	struct mips_vdso_image *image = current->thread.abi->vdso;
>  	struct mm_struct *mm = current->mm;
> -	unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr;
> +	unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn;
>  	struct vm_area_struct *vma;
> -	struct resource gic_res;
>  	int ret;
>  
>  	if (down_write_killable(&mm->mmap_sem))
> @@ -127,7 +126,7 @@ int arch_setup_additional_pages(struct l
>  	 * only map a page even though the total area is 64K, as we only need
>  	 * the counter registers at the start.
>  	 */
> -	gic_size = gic_present ? PAGE_SIZE : 0;
> +	gic_size = mips_gic_present() ? PAGE_SIZE : 0;
>  	vvar_size = gic_size + PAGE_SIZE;
>  	size = vvar_size + image->size;
>  
> @@ -168,13 +167,9 @@ int arch_setup_additional_pages(struct l
>  
>  	/* Map GIC user page. */
>  	if (gic_size) {
> -		ret = gic_get_usm_range(&gic_res);
> -		if (ret)
> -			goto out;
> +		gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;
>  
> -		ret = io_remap_pfn_range(vma, base,
> -					 gic_res.start >> PAGE_SHIFT,
> -					 gic_size,
> +		ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
>  					 pgprot_noncached(PAGE_READONLY));
>  		if (ret)
>  			goto out;
> 
>