Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753635Ab2JOGSn (ORCPT ); Mon, 15 Oct 2012 02:18:43 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:55325 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752394Ab2JOGSm (ORCPT ); Mon, 15 Oct 2012 02:18:42 -0400 From: Alexey Kardashevskiy To: Benjamin Herrenschmidt Cc: Alexey Kardashevskiy , Paul Mackerras , Anton Blanchard , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH] powerpc: added DSCR support to ptrace Date: Mon, 15 Oct 2012 17:18:30 +1100 Message-Id: <1350281910-5238-1-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2744 Lines: 82 The DSCR (aka Data Stream Control Register) is supported on some server PowerPC chips and allow some control over the prefetch of data streams. The kernel already supports DSCR value per thread but there is also a need in a ability to change it from an external process for the specific pid. The patch adds new register index PT_DSCR (index=44) which can be set/get by: ptrace(PTRACE_POKEUSER, traced_process, PT_DSCR << 3, dscr); dscr = ptrace(PTRACE_PEEKUSER, traced_process, PT_DSCR << 3, NULL); Signed-off-by: Alexey Kardashevskiy --- arch/powerpc/include/asm/ptrace.h | 3 ++- arch/powerpc/kernel/ptrace.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index 84cc784..946c556 100644 --- a/arch/powerpc/include/asm/ptrace.h +++ b/arch/powerpc/include/asm/ptrace.h @@ -276,7 +276,8 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, #define PT_DAR 41 #define PT_DSISR 42 #define PT_RESULT 43 -#define PT_REGS_COUNT 44 +#define PT_DSCR 44 +#define PT_REGS_COUNT 45 #define PT_FPR0 48 /* each FP reg occupies 2 slots in this space */ diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index 8d8e028..4798acf 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -179,6 +179,17 @@ static int set_user_msr(struct task_struct *task, unsigned long msr) return 0; } +static unsigned long get_user_dscr(struct task_struct *task) +{ + return task->thread.dscr; +} + +static int set_user_dscr(struct task_struct *task, unsigned long dscr) +{ + task->thread.dscr = dscr; + return 0; +} + /* * We prevent mucking around with the reserved area of trap * which are used internally by the kernel. @@ -200,6 +211,9 @@ unsigned long ptrace_get_reg(struct task_struct *task, int regno) if (regno == PT_MSR) return get_user_msr(task); + if (regno == PT_DSCR) + return get_user_dscr(task); + if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long))) return ((unsigned long *)task->thread.regs)[regno]; @@ -218,6 +232,8 @@ int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data) return set_user_msr(task, data); if (regno == PT_TRAP) return set_user_trap(task, data); + if (regno == PT_DSCR) + return set_user_dscr(task, data); if (regno <= PT_MAX_PUT_REG) { ((unsigned long *)task->thread.regs)[regno] = data; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/