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Subject[RFC 3/3] mmiotrace full patch, preview 3
Whoops, sorry, this is of course titled RFC 3/3.


On Mon, 28 Apr 2008 21:58:54 +0300
Pekka Paalanen <pq@iki.fi> wrote:

> On Mon, 28 Apr 2008 21:45:04 +0300
> Pekka Paalanen <pq@iki.fi> wrote:
>
> > Hi all,
> >
> > this is the third full mmiotrace patch set for review (a bit late, sorry).
> > These patches do not apply to any git tree that I know of, but after Ingo
> > pushes a new version of his sched-devel/latest tree, these patches should
> > be subtractable from there.
> ...
> > This first patch adds the bulk of the new code, only introducing new files.
> > The second patch establishes the interfaces to the ftrace framework, and
> > the third patch hooks everything up into the Kbuild system, page fault
> > handler, and ioremap functions.
>
> arch/x86/Kconfig.debug | 28 ++++++++++++++++++++++++++++
> arch/x86/mm/Makefile | 5 +++++
> arch/x86/mm/fault.c | 13 +++++++++++++
> arch/x86/mm/ioremap.c | 9 ++++++++-
> arch/x86/mm/pageattr.c | 1 +
> 5 files changed, 55 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index 1f237d2..fb0794e 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -170,6 +170,34 @@ config IOMMU_LEAK
> Add a simple leak tracer to the IOMMU code. This is useful when you
> are debugging a buggy device driver that leaks IOMMU mappings.
>
> +config MMIOTRACE_HOOKS
> + bool
> +
> +config MMIOTRACE
> + bool "Memory mapped IO tracing"
> + depends on DEBUG_KERNEL && PCI
> + select TRACING
> + select MMIOTRACE_HOOKS
> + default y
> + help
> + Mmiotrace traces Memory Mapped I/O access and is meant for
> + debugging and reverse engineering. It is called from the ioremap
> + implementation and works via page faults. Tracing is disabled by
> + default and can be enabled at run-time.
> +
> + See Documentation/tracers/mmiotrace.txt.
> + If you are not helping to develop drivers, say N.
> +
> +config MMIOTRACE_TEST
> + tristate "Test module for mmiotrace"
> + depends on MMIOTRACE && m
> + help
> + This is a dumb module for testing mmiotrace. It is very dangerous
> + as it will write garbage to IO memory starting at a given address.
> + However, it should be safe to use on e.g. unused portion of VRAM.
> +
> + Say N, unless you absolutely know what you are doing.
> +
> #
> # IO delay types:
> #
> diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
> index b7b3e4c..07dab50 100644
> --- a/arch/x86/mm/Makefile
> +++ b/arch/x86/mm/Makefile
> @@ -8,6 +8,11 @@ obj-$(CONFIG_X86_PTDUMP) += dump_pagetables.o
>
> obj-$(CONFIG_HIGHMEM) += highmem_32.o
>
> +obj-$(CONFIG_MMIOTRACE_HOOKS) += kmmio.o
> +obj-$(CONFIG_MMIOTRACE) += mmiotrace.o
> +mmiotrace-y := pf_in.o mmio-mod.o
> +obj-$(CONFIG_MMIOTRACE_TEST) += testmmiotrace.o
> +
> ifeq ($(CONFIG_X86_32),y)
> obj-$(CONFIG_NUMA) += discontig_32.o
> else
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index 4145597..0440dce 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -26,6 +26,7 @@
> #include <linux/uaccess.h>
> #include <linux/kdebug.h>
> #include <linux/magic.h>
> +#include <linux/mmiotrace.h>
>
> #include <asm/system.h>
> #include <asm/desc.h>
> @@ -51,6 +52,16 @@
> #define PF_RSVD (1<<3)
> #define PF_INSTR (1<<4)
>
> +static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
> +{
> +#ifdef CONFIG_MMIOTRACE_HOOKS
> + if (unlikely(is_kmmio_active()))
> + if (kmmio_handler(regs, addr) == 1)
> + return -1;
> +#endif
> + return 0;
> +}
> +
> static inline int notify_page_fault(struct pt_regs *regs)
> {
> #ifdef CONFIG_KPROBES
> @@ -623,6 +634,8 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
>
> if (notify_page_fault(regs))
> return;
> + if (unlikely(kmmio_fault(regs, address)))
> + return;
>
> /*
> * We fault-in kernel-space virtual memory on-demand. The
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index d176b23..68b287d 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -12,6 +12,7 @@
> #include <linux/module.h>
> #include <linux/slab.h>
> #include <linux/vmalloc.h>
> +#include <linux/mmiotrace.h>
>
> #include <asm/cacheflush.h>
> #include <asm/e820.h>
> @@ -126,6 +127,7 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
> unsigned long new_prot_val;
> pgprot_t prot;
> int retval;
> + void __iomem *ret_addr;
>
> /* Don't allow wraparound or zero size */
> last_addr = phys_addr + size - 1;
> @@ -229,7 +231,10 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
> return NULL;
> }
>
> - return (void __iomem *) (vaddr + offset);
> + ret_addr = (void __iomem *) (vaddr + offset);
> + mmiotrace_ioremap(phys_addr, size, ret_addr);
> +
> + return ret_addr;
> }
>
> /**
> @@ -306,6 +311,8 @@ void iounmap(volatile void __iomem *addr)
> addr < phys_to_virt(ISA_END_ADDRESS))
> return;
>
> + mmiotrace_iounmap(addr);
> +
> addr = (volatile void __iomem *)
> (PAGE_MASK & (unsigned long __force)addr);
>
> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
> index bd5e05c..099374b 100644
> --- a/arch/x86/mm/pageattr.c
> +++ b/arch/x86/mm/pageattr.c
> @@ -227,6 +227,7 @@ pte_t *lookup_address(unsigned long address, unsigned int *level)
>
> return pte_offset_kernel(pmd, address);
> }
> +EXPORT_SYMBOL_GPL(lookup_address);
>
> /*
> * Set the new pmd in all the pgds we know about:
>


--
Pekka Paalanen
http://www.iki.fi/pq/


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