| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20240410204337739-0700.eberman@hu-eberman-lv.qualcomm.com>
Date: Wed, 10 Apr 2024 20:54:24 -0700
From: Elliot Berman <quic_eberman@...cinc.com>
To: Stephen Boyd <swboyd@...omium.org>
CC: Caleb Connolly <caleb.connolly@...aro.org>,
Stephan Gerhold
<stephan@...hold.net>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Volodymyr
Babchuk <Volodymyr_Babchuk@...m.com>,
Bjorn Andersson <andersson@...nel.org>,
"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Douglas
Anderson <dianders@...omium.org>,
Rob Clark <robdclark@...il.com>
Subject: Re: [PATCH] soc: qcom: cmd-db: map shared memory as WT, not WB
On Thu, Mar 28, 2024 at 07:40:49PM -0500, Stephen Boyd wrote:
> Quoting Stephan Gerhold (2024-03-28 02:58:56)
> >
> > FWIW: This old patch series from Stephen Boyd is closely related:
> > https://lore.kernel.org/linux-arm-msm/20190910160903.65694-1-swboyd@chromium.org/
> >
> > > The main use case I have is to map the command-db memory region on
> > > Qualcomm devices with a read-only mapping. It's already a const marked
> > > pointer and the API returns const pointers as well, so this series
> > > makes sure that even stray writes can't modify the memory.
> >
> > Stephen, what was the end result of that patch series? Mapping the
> > cmd-db read-only sounds cleaner than trying to be lucky with the right
> > set of cache flags.
> >
>
> I dropped it because I got busy with other stuff. Feel free to pick it
> back up. It looks like the part where I left off was where we had to
> make the API fallback to mapping the memory as writeable if read-only
> isn't supported on the architecture.
[...]
> The other weird thing was that we passed both MEMREMAP_RO and
> MEMREMAP_WB to indicate what sort of fallback we want. Perhaps that can
> be encoded in the architecture layer so that you get the closest thing
> to read-only memory (i.e. any sort of write side caching is removed) and
> you don't have to pass a fallback mapping type.
Was there any motivation for having the fallback? I suspect driver
owners that want to use MEMREMAP_RO will know which architectures the
driver is applicable to and also know whether MEMREMAP_RO would work.
> I also wanted to return a const pointer.
The stash looks mostly complete. Do you think it should be part of the
series or submitted separately?
>
> Here's my stash patch on top of the branch (from 2019!).
>
> ---8<----
> From: Stephen Boyd <swboyd@...omium.org>
> Date: Tue, 14 May 2019 13:22:01 -0700
> Subject: [PATCH] stash const iounmap
>
> ---
> arch/arm64/include/asm/io.h | 2 +-
> arch/arm64/mm/ioremap.c | 9 +++++----
> arch/x86/mm/ioremap.c | 2 +-
> drivers/firmware/google/vpd.c | 22 +++++++++++-----------
> drivers/soc/qcom/rmtfs_mem.c | 5 ++---
> include/asm-generic/io.h | 2 +-
> include/linux/io.h | 2 +-
> include/linux/mmiotrace.h | 2 +-
> kernel/iomem.c | 2 +-
> 9 files changed, 24 insertions(+), 24 deletions(-)
>
> diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
> index 245bd371e8dc..0fd4f1678300 100644
> --- a/arch/arm64/include/asm/io.h
> +++ b/arch/arm64/include/asm/io.h
> @@ -178,7 +178,7 @@ extern void __memset_io(volatile void __iomem *,
> int, size_t);
> * I/O memory mapping functions.
> */
> extern void __iomem *__ioremap(phys_addr_t phys_addr, size_t size,
> pgprot_t prot);
> -extern void __iounmap(volatile void __iomem *addr);
> +extern void __iounmap(const volatile void __iomem *addr);
> extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
>
> #define ioremap(addr, size) __ioremap((addr), (size),
> __pgprot(PROT_DEVICE_nGnRE))
> diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
> index c4c8cd4c31d4..e39fb2cb6042 100644
> --- a/arch/arm64/mm/ioremap.c
> +++ b/arch/arm64/mm/ioremap.c
> @@ -80,16 +80,17 @@ void __iomem *__ioremap(phys_addr_t phys_addr,
> size_t size, pgprot_t prot)
> }
> EXPORT_SYMBOL(__ioremap);
>
> -void __iounmap(volatile void __iomem *io_addr)
> +void __iounmap(const volatile void __iomem *io_addr)
> {
> - unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
> + const unsigned long addr = (const unsigned long)io_addr & PAGE_MASK;
> + const void *vaddr = (const void __force *)addr;
>
> /*
> * We could get an address outside vmalloc range in case
> * of ioremap_cache() reusing a RAM mapping.
> */
> - if (is_vmalloc_addr((void *)addr))
> - vunmap((void *)addr);
> + if (is_vmalloc_addr(vaddr))
> + vunmap(vaddr);
> }
> EXPORT_SYMBOL(__iounmap);
>
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index 0029604af8a4..e9a2910d0c63 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -392,7 +392,7 @@ EXPORT_SYMBOL(ioremap_prot);
> *
> * Caller must ensure there is only one unmapping for the same pointer.
> */
> -void iounmap(volatile void __iomem *addr)
> +void iounmap(const volatile void __iomem *addr)
> {
> struct vm_struct *p, *o;
>
> diff --git a/drivers/firmware/google/vpd.c b/drivers/firmware/google/vpd.c
> index c0c0b4e4e281..7428f189999e 100644
> --- a/drivers/firmware/google/vpd.c
> +++ b/drivers/firmware/google/vpd.c
> @@ -48,7 +48,7 @@ struct vpd_section {
> const char *name;
> char *raw_name; /* the string name_raw */
> struct kobject *kobj; /* vpd/name directory */
> - char *baseaddr;
> + const char *baseaddr;
> struct bin_attribute bin_attr; /* vpd/name_raw bin_attribute */
> struct list_head attribs; /* key/value in vpd_attrib_info list */
> };
> @@ -187,19 +187,19 @@ static int vpd_section_create_attribs(struct
> vpd_section *sec)
> return 0;
> }
>
> -static int vpd_section_init(const char *name, struct vpd_section *sec,
> +static int vpd_section_init(struct device *dev, const char *name,
> struct vpd_section *sec,
> phys_addr_t physaddr, size_t size)
> {
> int err;
>
> - sec->baseaddr = memremap(physaddr, size, MEMREMAP_WB);
> - if (!sec->baseaddr)
> - return -ENOMEM;
> + sec->baseaddr = devm_memremap(physaddr, size, MEMREMAP_RO | MEMREMAP_WB);
> + if (IS_ERR(sec->baseaddr))
> + return PTR_ERR(sec->baseaddr);
>
> sec->name = name;
>
> /* We want to export the raw partition with name ${name}_raw */
> - sec->raw_name = kasprintf(GFP_KERNEL, "%s_raw", name);
> + sec->raw_name = devm_kasprintf(GFP_KERNEL, "%s_raw", name);
> if (!sec->raw_name) {
> err = -ENOMEM;
> goto err_memunmap;
> @@ -252,11 +252,12 @@ static int vpd_section_destroy(struct vpd_section *sec)
> return 0;
> }
>
> -static int vpd_sections_init(phys_addr_t physaddr)
> +static int vpd_sections_init(struct coreboot_device *cdev)
> {
> struct vpd_cbmem __iomem *temp;
> struct vpd_cbmem header;
> int ret = 0;
> + phys_addr_t physaddr = cdev->cbmem_ref.cbmem_addr;
>
> temp = memremap(physaddr, sizeof(struct vpd_cbmem), MEMREMAP_WB);
> if (!temp)
> @@ -269,7 +270,7 @@ static int vpd_sections_init(phys_addr_t physaddr)
> return -ENODEV;
>
> if (header.ro_size) {
> - ret = vpd_section_init("ro", &ro_vpd,
> + ret = vpd_section_init(&cdev->dev, "ro", &ro_vpd,
> physaddr + sizeof(struct vpd_cbmem),
> header.ro_size);
> if (ret)
> @@ -294,10 +295,9 @@ static int vpd_probe(struct coreboot_device *dev)
> int ret;
>
> vpd_kobj = kobject_create_and_add("vpd", firmware_kobj);
> - if (!vpd_kobj)
> - return -ENOMEM;
> + if (!vpd_kobj) return -ENOMEM;
>
> - ret = vpd_sections_init(dev->cbmem_ref.cbmem_addr);
> + ret = vpd_sections_init(dev);
> if (ret) {
> kobject_put(vpd_kobj);
> return ret;
> diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
> index 6f5e8be9689c..137e5240d916 100644
> --- a/drivers/soc/qcom/rmtfs_mem.c
> +++ b/drivers/soc/qcom/rmtfs_mem.c
> @@ -212,10 +212,9 @@ static int qcom_rmtfs_mem_probe(struct
> platform_device *pdev)
> rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
> rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
>
> - rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
> - rmtfs_mem->size, MEMREMAP_WC);
> + rmtfs_mem->base = devm_memremap_reserved_mem(&pdev->dev,
> + MEMREMAP_WC);
> if (IS_ERR(rmtfs_mem->base)) {
> - dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
> ret = PTR_ERR(rmtfs_mem->base);
> goto put_device;
> }
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 303871651f8a..d675a574eeb3 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -982,7 +982,7 @@ static inline void __iomem *__ioremap(phys_addr_t
> offset, size_t size,
> #ifndef iounmap
> #define iounmap iounmap
>
> -static inline void iounmap(void __iomem *addr)
> +static inline void iounmap(const void __iomem *addr)
> {
> }
> #endif
> diff --git a/include/linux/io.h b/include/linux/io.h
> index 16c7f4498869..82e6c4d6bdd3 100644
> --- a/include/linux/io.h
> +++ b/include/linux/io.h
> @@ -163,7 +163,7 @@ enum {
> };
>
> void *memremap(resource_size_t offset, size_t size, unsigned long flags);
> -void memunmap(void *addr);
> +void memunmap(const void *addr);
>
> /*
> * On x86 PAT systems we have memory tracking that keeps track of
> diff --git a/include/linux/mmiotrace.h b/include/linux/mmiotrace.h
> index 88236849894d..04607c468b73 100644
> --- a/include/linux/mmiotrace.h
> +++ b/include/linux/mmiotrace.h
> @@ -47,7 +47,7 @@ extern int kmmio_handler(struct pt_regs *regs,
> unsigned long addr);
> /* Called from ioremap.c */
> extern void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
> void __iomem *addr);
> -extern void mmiotrace_iounmap(volatile void __iomem *addr);
> +extern void mmiotrace_iounmap(const volatile void __iomem *addr);
>
> /* For anyone to insert markers. Remember trailing newline. */
> extern __printf(1, 2) int mmiotrace_printk(const char *fmt, ...);
> diff --git a/kernel/iomem.c b/kernel/iomem.c
> index 8d3cf74a32cb..22d0fa336360 100644
> --- a/kernel/iomem.c
> +++ b/kernel/iomem.c
> @@ -130,7 +130,7 @@ void *memremap(resource_size_t offset, size_t
> size, unsigned long flags)
> }
> EXPORT_SYMBOL(memremap);
>
> -void memunmap(void *addr)
> +void memunmap(const void *addr)
> {
> if (is_vmalloc_addr(addr))
> iounmap((void __iomem *) addr);
>
> base-commit: 9e98c678c2d6ae3a17cb2de55d17f69dddaa231b
> prerequisite-patch-id: 62119e27c0c0686e02f0cb55c296b878fb7f5e47
> prerequisite-patch-id: bda32cfc1733c245ae3f141d7c27b18e4adcc628
> prerequisite-patch-id: b8f8097161bd15e87d54dcfbfa67b9ca1abc7204
> prerequisite-patch-id: cd374fb6e39941b8613d213b4a75909749409d63
> prerequisite-patch-id: d8dbc8485a0f86353a314ab5c22fc92d8eac1cc0
> prerequisite-patch-id: e539621b0eccf82aabf9891de69c30398abf76a0
> prerequisite-patch-id: 59d60033b80dec940201edd5aefed22726122a37
> prerequisite-patch-id: 0d16b23cec20eaab7f45ee84fd8d2950657dc72e
> --
> https://chromeos.dev
>
Powered by blists - more mailing lists