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Mon, 13 Jan 2020 17:08:45 +0000 (UTC) Message-Id: <0cb594bc696cc195996733004907aefc3a6e596c.1578934751.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [RFC PATCH v3 07/12] powerpc/vdso: simplify __get_datapage() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org Date: Mon, 13 Jan 2020 17:08:45 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200113_090848_224212_3EA00DC3 X-CRM114-Status: GOOD ( 13.89 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [93.17.236.30 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The VDSO datapage and the text pages are always located immediately next to each other, so it can be hardcoded without an indirection through __kernel_datapage_offset In order to ease things, move the data page in front like other arches, that way there is no need to know the size of the library to locate the data page. Before: clock-getres-realtime-coarse: vdso: 714 nsec/call clock-gettime-realtime-coarse: vdso: 792 nsec/call clock-gettime-realtime: vdso: 1243 nsec/call After: clock-getres-realtime-coarse: vdso: 699 nsec/call clock-gettime-realtime-coarse: vdso: 784 nsec/call clock-gettime-realtime: vdso: 1231 nsec/call Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/vdso.c | 53 +++++---------------------------- arch/powerpc/kernel/vdso32/datapage.S | 10 +++---- arch/powerpc/kernel/vdso32/vdso32.lds.S | 7 ++--- arch/powerpc/kernel/vdso64/datapage.S | 10 +++---- arch/powerpc/kernel/vdso64/vdso64.lds.S | 7 ++--- 5 files changed, 19 insertions(+), 68 deletions(-) diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 16a44bffe698..c093d90a222a 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -191,7 +191,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) * install_special_mapping or the perf counter mmap tracking code * will fail to recognise it as a vDSO (since arch_vma_name fails). */ - current->mm->context.vdso_base = vdso_base; + current->mm->context.vdso_base = vdso_base + PAGE_SIZE; /* * our vma flags don't have VM_WRITE so by default, the process isn't @@ -488,42 +488,6 @@ static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32, vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32"); } -static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32, - struct lib64_elfinfo *v64) -{ -#ifdef CONFIG_VDSO32 - Elf32_Sym *sym32; -#endif -#ifdef CONFIG_PPC64 - Elf64_Sym *sym64; - - sym64 = find_symbol64(v64, "__kernel_datapage_offset"); - if (sym64 == NULL) { - printk(KERN_ERR "vDSO64: Can't find symbol " - "__kernel_datapage_offset !\n"); - return -1; - } - *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) = - (vdso64_pages << PAGE_SHIFT) - - (sym64->st_value - VDSO64_LBASE); -#endif /* CONFIG_PPC64 */ - -#ifdef CONFIG_VDSO32 - sym32 = find_symbol32(v32, "__kernel_datapage_offset"); - if (sym32 == NULL) { - printk(KERN_ERR "vDSO32: Can't find symbol " - "__kernel_datapage_offset !\n"); - return -1; - } - *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) = - (vdso32_pages << PAGE_SHIFT) - - (sym32->st_value - VDSO32_LBASE); -#endif - - return 0; -} - - static __init int vdso_fixup_features(struct lib32_elfinfo *v32, struct lib64_elfinfo *v64) { @@ -624,9 +588,6 @@ static __init int vdso_setup(void) if (vdso_do_find_sections(&v32, &v64)) return -1; - if (vdso_fixup_datapage(&v32, &v64)) - return -1; - if (vdso_fixup_features(&v32, &v64)) return -1; @@ -771,26 +732,26 @@ static int __init vdso_init(void) vdso32_pagelist = kcalloc(vdso32_pages + 2, sizeof(struct page *), GFP_KERNEL); BUG_ON(vdso32_pagelist == NULL); + vdso32_pagelist[0] = virt_to_page(vdso_data); for (i = 0; i < vdso32_pages; i++) { struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); get_page(pg); - vdso32_pagelist[i] = pg; + vdso32_pagelist[i + 1] = pg; } - vdso32_pagelist[i++] = virt_to_page(vdso_data); - vdso32_pagelist[i] = NULL; + vdso32_pagelist[i + 1] = NULL; #endif #ifdef CONFIG_PPC64 vdso64_pagelist = kcalloc(vdso64_pages + 2, sizeof(struct page *), GFP_KERNEL); BUG_ON(vdso64_pagelist == NULL); + vdso64_pagelist[0] = virt_to_page(vdso_data); for (i = 0; i < vdso64_pages; i++) { struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); get_page(pg); - vdso64_pagelist[i] = pg; + vdso64_pagelist[i + 1] = pg; } - vdso64_pagelist[i++] = virt_to_page(vdso_data); - vdso64_pagelist[i] = NULL; + vdso64_pagelist[i + 1] = NULL; #endif /* CONFIG_PPC64 */ get_page(virt_to_page(vdso_data)); diff --git a/arch/powerpc/kernel/vdso32/datapage.S b/arch/powerpc/kernel/vdso32/datapage.S index 6c7401bd284e..d839aa1a4f01 100644 --- a/arch/powerpc/kernel/vdso32/datapage.S +++ b/arch/powerpc/kernel/vdso32/datapage.S @@ -12,9 +12,6 @@ #include .text - .global __kernel_datapage_offset; -__kernel_datapage_offset: - .long 0 V_FUNCTION_BEGIN(__get_datapage) .cfi_startproc @@ -31,10 +28,11 @@ V_FUNCTION_BEGIN(__get_datapage) data_page_branch: mflr r3 mtlr r0 - addi r3, r3, __kernel_datapage_offset-data_page_branch - lwz r0,0(r3) +#if CONFIG_PPC_PAGE_SHIFT > 14 + addis r3, r3, (_vdso_datapage - data_page_branch)@ha +#endif + addi r3, r3, (_vdso_datapage - data_page_branch)@l .cfi_restore lr - add r3,r0,r3 blr .cfi_endproc V_FUNCTION_END(__get_datapage) diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S index 9400b182e163..f09c2354bd21 100644 --- a/arch/powerpc/kernel/vdso32/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S @@ -4,6 +4,7 @@ * library */ #include +#include #ifdef __LITTLE_ENDIAN__ OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle") @@ -15,6 +16,7 @@ ENTRY(_start) SECTIONS { + PROVIDE(_vdso_datapage = . - PAGE_SIZE); . = VDSO32_LBASE + SIZEOF_HEADERS; .hash : { *(.hash) } :text @@ -138,11 +140,6 @@ VERSION { VDSO_VERSION_STRING { global: - /* - * Has to be there for the kernel to find - */ - __kernel_datapage_offset; - __kernel_get_syscall_map; #if defined(CONFIG_PPC32) && !defined(CONFIG_PPC_BOOK3S_601) __kernel_gettimeofday; diff --git a/arch/powerpc/kernel/vdso64/datapage.S b/arch/powerpc/kernel/vdso64/datapage.S index 4808ce9eeb3d..8c41e1a93980 100644 --- a/arch/powerpc/kernel/vdso64/datapage.S +++ b/arch/powerpc/kernel/vdso64/datapage.S @@ -12,9 +12,6 @@ #include .text -.global __kernel_datapage_offset; -__kernel_datapage_offset: - .long 0 _GLOBAL(__get_datapage) .cfi_startproc @@ -31,10 +28,11 @@ _GLOBAL(__get_datapage) data_page_branch: mflr r3 mtlr r0 - addi r3, r3, __kernel_datapage_offset-data_page_branch - lwz r0,0(r3) +#if CONFIG_PPC_PAGE_SHIFT > 14 + addis r3, r3, (_vdso_datapage - data_page_branch)@ha +#endif + addi r3, r3, (_vdso_datapage - data_page_branch)@l .cfi_restore lr - add r3,r0,r3 blr .cfi_endproc diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S index 256fb9720298..f58c7e2e9cbd 100644 --- a/arch/powerpc/kernel/vdso64/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S @@ -4,6 +4,7 @@ * library */ #include +#include #ifdef __LITTLE_ENDIAN__ OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle") @@ -15,6 +16,7 @@ ENTRY(_start) SECTIONS { + PROVIDE(_vdso_datapage = . - PAGE_SIZE); . = VDSO64_LBASE + SIZEOF_HEADERS; .hash : { *(.hash) } :text @@ -138,11 +140,6 @@ VERSION { VDSO_VERSION_STRING { global: - /* - * Has to be there for the kernel to find - */ - __kernel_datapage_offset; - __kernel_get_syscall_map; __kernel_gettimeofday; __kernel_clock_gettime;