Re: [PATCH v2] perf/x86/uncore: fix compilation warning in snb_uncore_imc_init_box()

From: Kirill A. Shutemov
Date: Tue Apr 15 2014 - 16:38:20 EST

On Wed, Mar 12, 2014 at 12:53:30AM +0100, Stephane Eranian wrote:
>
> This patch fixes a compilation problem (unused variable) with the
> new SNB/IVB/HSW uncore IMC code.
>
> In V2, we simplify the fix as suggested by Peter Zjilstra.
>
> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
> --
>
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> index 3e5b240..d614f6b 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> @@ -1722,15 +1722,16 @@ static struct attribute_group snb_uncore_imc_format_group = {
> static void snb_uncore_imc_init_box(struct intel_uncore_box *box)
> {
> struct pci_dev *pdev = box->pci_dev;
> - u32 addr_lo, addr_hi;
> + int where = SNB_UNCORE_PCI_IMC_BAR_OFFSET;
> + u32 pci_dword;
> resource_size_t addr;
>
> - pci_read_config_dword(pdev, SNB_UNCORE_PCI_IMC_BAR_OFFSET, &addr_lo);
> - addr = addr_lo;
> + pci_read_config_dword(pdev, where, &pci_dword);
> + addr = pci_dword;
>
> #ifdef CONFIG_PHYS_ADDR_T_64BIT
> - pci_read_config_dword(pdev, SNB_UNCORE_PCI_IMC_BAR_OFFSET+4, &addr_hi);
> - addr = ((resource_size_t)addr_hi << 32) | addr_lo;
> + pci_read_config_dword(pdev, where + 4, &pci_dword);
> + addr |= ((resource_size_t)pci_dword << 32);
> #endif
>
> addr &= ~(PAGE_SIZE - 1);

I see the warning on my laptop (X1 Carbon), which probably related to the commit:

[ 0.559204] ------------[ cut here ]------------
[ 0.559216] WARNING: CPU: 2 PID: 1 at /home/kas/git/public/linux/arch/x86/mm/ioremap.c:171 __ioremap_caller+0x2e3/0x390()
[ 0.559225] Info: mapping multiple BARs. Your kernel is fine.
[ 0.559230] Modules linked in:

[ 0.559238] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 3.15.0-rc1-00012-g55101e2d6ce1 #38
[ 0.559246] Hardware name: LENOVO 3460CC6/3460CC6, BIOS G6ET93WW (2.53 ) 02/04/2013
[ 0.559254] 0000000000000009 ffff8801182f3b60 ffffffff81a2274e ffff8801182f3ba8
[ 0.559264] ffff8801182f3b98 ffffffff810db97d ffffc90000658000 00000000fed16000
[ 0.559274] ffffc90000658000 ffffc90000658000 0000000000006000 ffff8801182f3bf8
[ 0.559284] Call Trace:
[ 0.559293] [<ffffffff81a2274e>] dump_stack+0x4d/0x6f
[ 0.559300] [<ffffffff810db97d>] warn_slowpath_common+0x7d/0xa0
[ 0.559307] [<ffffffff810db9ec>] warn_slowpath_fmt+0x4c/0x50
[ 0.559316] [<ffffffff810e39dc>] ? iomem_map_sanity_check+0xac/0xe0
[ 0.559324] [<ffffffff810a8823>] __ioremap_caller+0x2e3/0x390
[ 0.559332] [<ffffffff810a88e7>] ioremap_nocache+0x17/0x20
[ 0.559339] [<ffffffff81083845>] snb_uncore_imc_init_box+0x65/0x90
[ 0.559348] [<ffffffff810827c8>] uncore_pci_probe+0xd8/0x1b0
[ 0.559356] [<ffffffff8140f255>] local_pci_probe+0x45/0xa0
[ 0.559364] [<ffffffff8140e9c5>] ? pci_match_device+0xc5/0xd0
[ 0.559371] [<ffffffff8140f389>] pci_device_probe+0xd9/0x130
[ 0.559379] [<ffffffff81598987>] driver_probe_device+0x87/0x390
[ 0.559385] [<ffffffff81598d63>] __driver_attach+0x93/0xa0
[ 0.559392] [<ffffffff81598cd0>] ? __device_attach+0x40/0x40
[ 0.559401] [<ffffffff815968bb>] bus_for_each_dev+0x6b/0xb0
[ 0.559408] [<ffffffff815983ae>] driver_attach+0x1e/0x20
[ 0.559415] [<ffffffff81597f88>] bus_add_driver+0x188/0x260
[ 0.559425] [<ffffffff8237e179>] ? uncore_pmu_register+0xdb/0xdb
[ 0.559432] [<ffffffff815993c4>] driver_register+0x64/0xf0
[ 0.559439] [<ffffffff8237e179>] ? uncore_pmu_register+0xdb/0xdb
[ 0.559446] [<ffffffff8140eb30>] __pci_register_driver+0x60/0x70
[ 0.559454] [<ffffffff8237e2ee>] intel_uncore_init+0x175/0x42b
[ 0.559461] [<ffffffff8237e179>] ? uncore_pmu_register+0xdb/0xdb
[ 0.559470] [<ffffffff8100216a>] do_one_initcall+0xfa/0x1b0
[ 0.559479] [<ffffffff811035e5>] ? parse_args+0x225/0x3f0
[ 0.559487] [<ffffffff8236e17c>] kernel_init_freeable+0x1da/0x25f
[ 0.559495] [<ffffffff8236d8e5>] ? do_early_param+0x88/0x88
[ 0.559504] [<ffffffff81a13060>] ? rest_init+0x140/0x140
[ 0.559511] [<ffffffff81a1306e>] kernel_init+0xe/0xf0
[ 0.559519] [<ffffffff81a380bc>] ret_from_fork+0x7c/0xb0
[ 0.559526] [<ffffffff81a13060>] ? rest_init+0x140/0x140
[ 0.559538] ---[ end trace 2d7d94a103087769 ]---

--
Kirill A. Shutemov
--
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