From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Lee, Chun-Yi" Subject: [PATCH 03/14] rtc: block registration of rtc-cmos when CMOS RTC Not Present Date: Thu, 19 Dec 2013 15:44:02 +0800 Message-ID: <1387439053-8711-4-git-send-email-jlee@suse.com> References: <1387439053-8711-1-git-send-email-jlee@suse.com> Return-path: In-Reply-To: <1387439053-8711-1-git-send-email-jlee-IBi9RG/b67k@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Rafael J. Wysocki" , Alessandro Zummo , "H. Peter Anvin" , Matt Fleming , Matthew Garrett Cc: Elliott-VXdhtT5mjnY@public.gmane.org, samer.el-haj-mahmoud-VXdhtT5mjnY@public.gmane.org, Oliver Neukum , werner-IBi9RG/b67k@public.gmane.org, trenn-l3A5Bk7waGM@public.gmane.org, JBeulich-IBi9RG/b67k@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Lee, Chun-Yi" List-Id: linux-efi@vger.kernel.org We should not acess CMOS address when CMOS RTC Not Present bit set in FADT. The ee5872be patch didn't avoid rtc-cmos driver loaded when system support ACPI PNP PNP0B0* devices. So this patch block the registion of rtc-cmos driver to avoid user space access RTC through CMOS interface. Signed-off-by: Lee, Chun-Yi --- arch/x86/kernel/rtc.c | 20 ++++++++++++++++---- drivers/rtc/rtc-cmos.c | 9 +++++++++ 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index ca9622a..9b6c568 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -174,16 +174,27 @@ static __init int add_rtc_cmos(void) { "PNP0b00", "PNP0b01", "PNP0b02", }; struct pnp_dev *dev; struct pnp_id *id; - int i; + int i = 0; + bool found_pnp; pnp_for_each_dev(dev) { for (id = dev->id; id; id = id->next) { for (i = 0; i < ARRAY_SIZE(ids); i++) { - if (compare_pnp_id(id, ids[i]) != 0) - return 0; + if (compare_pnp_id(id, ids[i]) != 0) { + found_pnp = true; + goto found_pnp; + } } } } + +found_pnp: + if (found_pnp) { + if (acpi_gbl_FADT.header.revision >= 5 && + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) + pr_err(FW_BUG "Found %s device but CMOS RTC Not Present flag set\n", ids[i]); + return 0; + } #endif if (of_have_populated_dt()) return 0; @@ -193,7 +204,8 @@ static __init int add_rtc_cmos(void) return -ENODEV; #ifdef CONFIG_ACPI - if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) { + if (acpi_gbl_FADT.header.revision >= 5 && + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) { /* This warning can likely go away again in a year or two. */ pr_info("ACPI: not registering RTC platform device\n"); return -ENODEV; diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index f148762..3a84ca9 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -28,6 +28,9 @@ * interrupts disabled, holding the global rtc_lock, to exclude those * other drivers and utilities on correctly configured systems. */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include #include #include @@ -1144,6 +1147,12 @@ static int __init cmos_init(void) { int retval = 0; + if (acpi_gbl_FADT.header.revision >= 5 && + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) { + pr_info("ACPI CMOS RTC Not Present detected - not loading\n"); + return 0; + } + #ifdef CONFIG_PNP retval = pnp_register_driver(&cmos_pnp_driver); if (retval == 0) -- 1.6.4.2