From: Kees Cook <keescook@chromium.org> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Kees Cook <keescook@chromium.org>, Al Cooper <alcooperx@gmail.com>, Alan Stern <stern@rowland.harvard.edu>, linux-usb@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, Arnd Bergmann <arnd@arndb.de>, Florian Fainelli <f.fainelli@gmail.com>, Andy Shevchenko <andy.shevchenko@gmail.com>, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG Date: Tue, 17 Aug 2021 21:30:34 -0700 [thread overview] Message-ID: <20210818043035.1308062-3-keescook@chromium.org> (raw) In-Reply-To: <20210818043035.1308062-1-keescook@chromium.org> Refactor struct ehci_regs to avoid accessing beyond the end of port_status. This change results in no difference in the resulting object code. Avoids several warnings when building with -Warray-bounds: drivers/usb/host/ehci-brcm.c: In function 'ehci_brcm_reset': drivers/usb/host/ehci-brcm.c:113:32: warning: array subscript 16 is above array bounds of 'u32[15]' {aka 'unsigned int[15]'} [-Warray-bounds] 113 | ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from drivers/usb/host/ehci.h:274, from drivers/usb/host/ehci-brcm.c:15: ./include/linux/usb/ehci_def.h:132:7: note: while referencing 'port_status' 132 | u32 port_status[HCS_N_PORTS_MAX]; | ^~~~~~~~~~~ Note that the documentation around this proprietary register is confusing. If "USB_EHCI_INSNREG00" is at port_status[0x0f], its offset would be 0x80 (not 0x90). The code uses port_status[0x10], so is that not using "USB_EHCI_INSNREG00"? Perhaps port_status[0x10] is USB_EHCI_INSNREG01 and port_status[0x12] is USB_EHCI_INSNREG03? If so, the union could be adjusted to better represent the layout. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Cooper <alcooperx@gmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: linux-usb@vger.kernel.org Cc: bcm-kernel-feedback-list@broadcom.com Suggested-by: Arnd Bergmann <arnd@arndb.de> Fixes: 9df231511bd6 ("usb: ehci: Add new EHCI driver for Broadcom STB SoC's") Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/usb/host/ehci-brcm.c | 11 +++++------ include/linux/usb/ehci_def.h | 16 ++++++++++++++-- 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/usb/host/ehci-brcm.c b/drivers/usb/host/ehci-brcm.c index 3e0ebe8cc649..5d232d3701f9 100644 --- a/drivers/usb/host/ehci-brcm.c +++ b/drivers/usb/host/ehci-brcm.c @@ -110,8 +110,8 @@ static int ehci_brcm_reset(struct usb_hcd *hcd) * bus usage * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 */ - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); return ehci_setup(hcd); } @@ -223,11 +223,10 @@ static int __maybe_unused ehci_brcm_resume(struct device *dev) /* * SWLINUX-1705: Avoid OUT packet underflows during high memory * bus usage - * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 - * @ 0x90 + * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 */ - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); ehci_resume(hcd, false); diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h index 5398f571113b..86f0909cab99 100644 --- a/include/linux/usb/ehci_def.h +++ b/include/linux/usb/ehci_def.h @@ -182,11 +182,23 @@ struct ehci_regs { * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to * PORTSCx */ - /* HOSTPC: offset 0x84 */ - u32 hostpc[HCS_N_PORTS_MAX]; + union { + /* HOSTPC: offset 0x84 */ + u32 hostpc[HCS_N_PORTS_MAX]; #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ #define HOSTPC_PSPD (3<<25) /* Port speed detection */ + /* + * This was originally documented as: + * "port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90" + * but this doesn't make sense: the code was using + * port_status[0x10]. port_status[0x0f] would be reserved4. + * Also, none of these are near 0x90. port_status[0x10] is + * offset 0x84, and port_status[0x0f] would be 0x80. + */ + u32 brcm_insnreg[3]; + }; + u32 reserved5[2]; /* USBMODE_EX: offset 0xc8 */ -- 2.30.2
next prev parent reply other threads:[~2021-08-18 4:30 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-18 4:30 [PATCH 0/2] USB: EHCI: Add register array bounds to HCS ports Kees Cook 2021-08-18 4:30 ` [PATCH 1/2] " Kees Cook 2021-08-18 9:48 ` Andy Shevchenko 2021-08-18 15:02 ` Alan Stern 2021-08-18 14:44 ` Alan Stern 2021-08-18 17:17 ` Kees Cook 2021-08-18 4:30 ` Kees Cook [this message] 2021-08-18 14:57 ` [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG Alan Stern 2021-08-18 17:15 ` Kees Cook
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