[PATCH] RISC-V: Add address map dumper

[PATCH] RISC-V: Add address map dumper

[Yash Shah]

Add support for dumping the kernel address space layout to the console.
User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual memory region
into dmesg buffer during boot-up.

Signed-off-by: Yash Shah <yash.shah@sifive.com>
---
This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive Unleashed
board.
---
 arch/riscv/Kconfig.debug |  9 +++++++++
 arch/riscv/mm/init.c     | 30 ++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug
index e69de29..cdedfd3 100644
--- a/arch/riscv/Kconfig.debug
+++ b/arch/riscv/Kconfig.debug
@@ -0,0 +1,9 @@
+config DEBUG_VM_LAYOUT
+	bool "Print virtual memory layout on boot up"
+	depends on DEBUG_KERNEL
+	help
+	  Say Y here if you want to dump the kernel virtual memory layout to
+	  dmesg log on boot up. This information is only useful for kernel
+	  developers who are working in architecture specific areas of the
+	  kernel. It is probably not a good idea to enable this feature in a
+	  production kernel.
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 79cfb35..fcb8144 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -55,6 +55,36 @@ void __init mem_init(void)
 	memblock_free_all();
 
 	mem_init_print_info(NULL);
+#ifdef CONFIG_DEBUG_VM_LAYOUT
+#define MLK(b, t) b, t, (((t) - (b)) >> 10)
+#define MLM(b, t) b, t, (((t) - (b)) >> 20)
+#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
+
+
+	pr_notice("Virtual kernel memory layout:\n"
+			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+			"    vmemmap : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+			"      .init : 0x%px - 0x%px   (%4td kB)\n"
+			"      .text : 0x%px - 0x%px   (%4td kB)\n"
+			"      .data : 0x%px - 0x%px   (%4td kB)\n"
+			"       .bss : 0x%px - 0x%px   (%4td kB)\n",
+
+			MLK(FIXADDR_START, FIXADDR_TOP),
+			MLM(VMEMMAP_START, VMEMMAP_END),
+			MLM(VMALLOC_START, VMALLOC_END),
+			MLM(PAGE_OFFSET, (unsigned long)high_memory),
+
+			MLK_ROUNDUP(__init_begin, __init_end),
+			MLK_ROUNDUP(_text, _etext),
+			MLK_ROUNDUP(_sdata, _edata),
+			MLK_ROUNDUP(__bss_start, __bss_stop));
+
+#undef MLK
+#undef MLM
+#undef MLK_ROUNDUP
+#endif
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
-- 
2.7.4

Re: [PATCH] RISC-V: Add address map dumper

[Logan Gunthorpe]

On 2019-11-10 10:27 p.m., Yash Shah wrote:
> Add support for dumping the kernel address space layout to the console.
> User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual memory region
> into dmesg buffer during boot-up.

Cool, I'd find this useful. Though, is there any reason we don't do this
more generally for all architectures?

> Signed-off-by: Yash Shah <yash.shah@sifive.com>
> ---
> This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive Unleashed
> board.
> ---
>  arch/riscv/Kconfig.debug |  9 +++++++++
>  arch/riscv/mm/init.c     | 30 ++++++++++++++++++++++++++++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug
> index e69de29..cdedfd3 100644
> --- a/arch/riscv/Kconfig.debug
> +++ b/arch/riscv/Kconfig.debug
> @@ -0,0 +1,9 @@
> +config DEBUG_VM_LAYOUT
> +	bool "Print virtual memory layout on boot up"
> +	depends on DEBUG_KERNEL
> +	help
> +	  Say Y here if you want to dump the kernel virtual memory layout to
> +	  dmesg log on boot up. This information is only useful for kernel
> +	  developers who are working in architecture specific areas of the
> +	  kernel. It is probably not a good idea to enable this feature in a
> +	  production kernel.
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 79cfb35..fcb8144 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -55,6 +55,36 @@ void __init mem_init(void)
>  	memblock_free_all();
>  
>  	mem_init_print_info(NULL);
> +#ifdef CONFIG_DEBUG_VM_LAYOUT

Generally, it's best to avoid #ifdefs inside functions, it's even
counter-indicated in the style guide[1].

> +#define MLK(b, t) b, t, (((t) - (b)) >> 10)
> +#define MLM(b, t) b, t, (((t) - (b)) >> 20)
> +#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)

I personally find these inline defines rather ugly. Maybe it would be
better to have a helper function that prints a single line. Also seems
like MLK and MLK_ROUNDUP could be the same assuming the entries in MLK
are aligned...

> +
> +	pr_notice("Virtual kernel memory layout:\n"
> +			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
> +			"    vmemmap : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> +			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> +			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> +			"      .init : 0x%px - 0x%px   (%4td kB)\n"
> +			"      .text : 0x%px - 0x%px   (%4td kB)\n"
> +			"      .data : 0x%px - 0x%px   (%4td kB)\n"
> +			"       .bss : 0x%px - 0x%px   (%4td kB)\n",
> +
> +			MLK(FIXADDR_START, FIXADDR_TOP),
> +			MLM(VMEMMAP_START, VMEMMAP_END),
> +			MLM(VMALLOC_START, VMALLOC_END),
> +			MLM(PAGE_OFFSET, (unsigned long)high_memory),
> +
> +			MLK_ROUNDUP(__init_begin, __init_end),
> +			MLK_ROUNDUP(_text, _etext),
> +			MLK_ROUNDUP(_sdata, _edata),
> +			MLK_ROUNDUP(__bss_start, __bss_stop));
> +
> +#undef MLK
> +#undef MLM
> +#undef MLK_ROUNDUP
> +#endif
>  }
>  
>  #ifdef CONFIG_BLK_DEV_INITRD

Thanks,

Logan

[1]
https://www.kernel.org/doc/html/latest/process/coding-style.html#conditional-compilation

Re: [PATCH] RISC-V: Add address map dumper

[Mike Rapoport]

On Mon, Nov 11, 2019 at 11:14:30AM -0700, Logan Gunthorpe wrote:
> 
> 
> On 2019-11-10 10:27 p.m., Yash Shah wrote:
> > Add support for dumping the kernel address space layout to the console.
> > User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual memory region
> > into dmesg buffer during boot-up.
> 
> Cool, I'd find this useful. Though, is there any reason we don't do this
> more generally for all architectures?

Some architectures do this, some don't. I don't think there's a particular
reason we don't do this generally, it just evolved that way :)
 
> > Signed-off-by: Yash Shah <yash.shah@sifive.com>
> > ---
> > This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive Unleashed
> > board.
> > ---
> >  arch/riscv/Kconfig.debug |  9 +++++++++
> >  arch/riscv/mm/init.c     | 30 ++++++++++++++++++++++++++++++
> >  2 files changed, 39 insertions(+)
> > 
> > diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug
> > index e69de29..cdedfd3 100644
> > --- a/arch/riscv/Kconfig.debug
> > +++ b/arch/riscv/Kconfig.debug
> > @@ -0,0 +1,9 @@
> > +config DEBUG_VM_LAYOUT
> > +	bool "Print virtual memory layout on boot up"
> > +	depends on DEBUG_KERNEL
> > +	help
> > +	  Say Y here if you want to dump the kernel virtual memory layout to
> > +	  dmesg log on boot up. This information is only useful for kernel
> > +	  developers who are working in architecture specific areas of the
> > +	  kernel. It is probably not a good idea to enable this feature in a
> > +	  production kernel.
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > index 79cfb35..fcb8144 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -55,6 +55,36 @@ void __init mem_init(void)
> >  	memblock_free_all();
> >  
> >  	mem_init_print_info(NULL);
> > +#ifdef CONFIG_DEBUG_VM_LAYOUT
> 
> Generally, it's best to avoid #ifdefs inside functions, it's even
> counter-indicated in the style guide[1].
> 
> > +#define MLK(b, t) b, t, (((t) - (b)) >> 10)
> > +#define MLM(b, t) b, t, (((t) - (b)) >> 20)
> > +#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
> 
> I personally find these inline defines rather ugly. Maybe it would be
> better to have a helper function that prints a single line. Also seems
> like MLK and MLK_ROUNDUP could be the same assuming the entries in MLK
> are aligned...
> 
> > +
> > +	pr_notice("Virtual kernel memory layout:\n"
> > +			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
> > +			"    vmemmap : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> > +			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> > +			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> > +			"      .init : 0x%px - 0x%px   (%4td kB)\n"
> > +			"      .text : 0x%px - 0x%px   (%4td kB)\n"
> > +			"      .data : 0x%px - 0x%px   (%4td kB)\n"
> > +			"       .bss : 0x%px - 0x%px   (%4td kB)\n",
> > +
> > +			MLK(FIXADDR_START, FIXADDR_TOP),
> > +			MLM(VMEMMAP_START, VMEMMAP_END),
> > +			MLM(VMALLOC_START, VMALLOC_END),
> > +			MLM(PAGE_OFFSET, (unsigned long)high_memory),
> > +
> > +			MLK_ROUNDUP(__init_begin, __init_end),
> > +			MLK_ROUNDUP(_text, _etext),
> > +			MLK_ROUNDUP(_sdata, _edata),
> > +			MLK_ROUNDUP(__bss_start, __bss_stop));
> > +
> > +#undef MLK
> > +#undef MLM
> > +#undef MLK_ROUNDUP
> > +#endif
> >  }
> >  
> >  #ifdef CONFIG_BLK_DEV_INITRD
> 
> Thanks,
> 
> Logan
> 
> [1]
> https://www.kernel.org/doc/html/latest/process/coding-style.html#conditional-compilation

-- 
Sincerely yours,
Mike.

Re: [PATCH] RISC-V: Add address map dumper

[Mike Rapoport]

Hi,

On Mon, Nov 11, 2019 at 05:27:25AM +0000, Yash Shah wrote:
> Add support for dumping the kernel address space layout to the console.
> User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual memory region
> into dmesg buffer during boot-up.
> 
> Signed-off-by: Yash Shah <yash.shah@sifive.com>
> ---
> This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive Unleashed
> board.
> ---
>  arch/riscv/Kconfig.debug |  9 +++++++++
>  arch/riscv/mm/init.c     | 30 ++++++++++++++++++++++++++++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug
> index e69de29..cdedfd3 100644
> --- a/arch/riscv/Kconfig.debug
> +++ b/arch/riscv/Kconfig.debug
> @@ -0,0 +1,9 @@
> +config DEBUG_VM_LAYOUT

I believe this could be enabled when CONFIG_DEBUG_VM=y without adding yet
another architecture specific Kconfig option.

> +	bool "Print virtual memory layout on boot up"
> +	depends on DEBUG_KERNEL
> +	help
> +	  Say Y here if you want to dump the kernel virtual memory layout to
> +	  dmesg log on boot up. This information is only useful for kernel
> +	  developers who are working in architecture specific areas of the
> +	  kernel. It is probably not a good idea to enable this feature in a
> +	  production kernel.
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 79cfb35..fcb8144 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -55,6 +55,36 @@ void __init mem_init(void)
>  	memblock_free_all();
>  
>  	mem_init_print_info(NULL);
> +#ifdef CONFIG_DEBUG_VM_LAYOUT
> +#define MLK(b, t) b, t, (((t) - (b)) >> 10)
> +#define MLM(b, t) b, t, (((t) - (b)) >> 20)
> +#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
> +
> +
> +	pr_notice("Virtual kernel memory layout:\n"
> +			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
> +			"    vmemmap : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> +			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> +			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
> +			"      .init : 0x%px - 0x%px   (%4td kB)\n"
> +			"      .text : 0x%px - 0x%px   (%4td kB)\n"
> +			"      .data : 0x%px - 0x%px   (%4td kB)\n"
> +			"       .bss : 0x%px - 0x%px   (%4td kB)\n",
> +
> +			MLK(FIXADDR_START, FIXADDR_TOP),
> +			MLM(VMEMMAP_START, VMEMMAP_END),
> +			MLM(VMALLOC_START, VMALLOC_END),
> +			MLM(PAGE_OFFSET, (unsigned long)high_memory),
> +
> +			MLK_ROUNDUP(__init_begin, __init_end),
> +			MLK_ROUNDUP(_text, _etext),
> +			MLK_ROUNDUP(_sdata, _edata),
> +			MLK_ROUNDUP(__bss_start, __bss_stop));
> +
> +#undef MLK
> +#undef MLM
> +#undef MLK_ROUNDUP
> +#endif
>  }
>  
>  #ifdef CONFIG_BLK_DEV_INITRD
> -- 
> 2.7.4
> 

-- 
Sincerely yours,
Mike.

RE: [PATCH] RISC-V: Add address map dumper

[Yash Shah]

> On 2019-11-10 10:27 p.m., Yash Shah wrote:
> > Add support for dumping the kernel address space layout to the console.
> > User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual
> memory
> > region into dmesg buffer during boot-up.
> 
> Cool, I'd find this useful. Though, is there any reason we don't do this more
> generally for all architectures?
> 
> > Signed-off-by: Yash Shah <yash.shah@sifive.com>
> > ---
> > This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive
> > Unleashed board.
> > ---
> >  arch/riscv/Kconfig.debug |  9 +++++++++
> >  arch/riscv/mm/init.c     | 30 ++++++++++++++++++++++++++++++
> >  2 files changed, 39 insertions(+)
> >
...
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index
> > 79cfb35..fcb8144 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -55,6 +55,36 @@ void __init mem_init(void)
> >  	memblock_free_all();
> >
> >  	mem_init_print_info(NULL);
> > +#ifdef CONFIG_DEBUG_VM_LAYOUT
> 
> Generally, it's best to avoid #ifdefs inside functions, it's even counter-
> indicated in the style guide[1].

Yes, I will move out the print logic as a separate function and guard it with #ifdefs

> 
> > +#define MLK(b, t) b, t, (((t) - (b)) >> 10) #define MLM(b, t) b, t,
> > +(((t) - (b)) >> 20) #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t)
> > +- (b)), SZ_1K)
> 
> I personally find these inline defines rather ugly. Maybe it would be better to
> have a helper function that prints a single line. Also seems like MLK and
> MLK_ROUNDUP could be the same assuming the entries in MLK are
> aligned...
> 

Sure, will convert this macros into helper inline functions and will also drop MLK_ROUNDUP.

> 
> Thanks,
> 
> Logan
> 

Thanks for your comments!

- Yash

> [1]
> https://www.kernel.org/doc/html/latest/process/coding-
> style.html#conditional-compilation
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

RE: [PATCH] RISC-V: Add address map dumper

[Yash Shah]

> -----Original Message-----
> From: Mike Rapoport <rppt@linux.ibm.com>
> Sent: 12 November 2019 03:27
> To: Yash Shah <yash.shah@sifive.com>
> Cc: Paul Walmsley ( Sifive) <paul.walmsley@sifive.com>; linux-
> riscv@lists.infradead.org; linux-kernel@vger.kernel.org;
> palmer@dabbelt.com; aou@eecs.berkeley.edu; Anup.Patel@wdc.com;
> logang@deltatee.com; ren_guo@c-sky.com; bmeng.cn@gmail.com;
> tglx@linutronix.de; Sachin Ghadi <sachin.ghadi@sifive.com>
> Subject: Re: [PATCH] RISC-V: Add address map dumper
> 
> Hi,
> 
> On Mon, Nov 11, 2019 at 05:27:25AM +0000, Yash Shah wrote:
> > Add support for dumping the kernel address space layout to the console.
> > User can enable CONFIG_DEBUG_VM_LAYOUT to dump the virtual
> memory
> > region into dmesg buffer during boot-up.
> >
> > Signed-off-by: Yash Shah <yash.shah@sifive.com>
> > ---
> > This patch is based on Linux 5.4-rc6 and tested on SiFive HiFive
> > Unleashed board.
> > ---
> >  arch/riscv/Kconfig.debug |  9 +++++++++
> >  arch/riscv/mm/init.c     | 30 ++++++++++++++++++++++++++++++
> >  2 files changed, 39 insertions(+)
> >
> > diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug index
> > e69de29..cdedfd3 100644
> > --- a/arch/riscv/Kconfig.debug
> > +++ b/arch/riscv/Kconfig.debug
> > @@ -0,0 +1,9 @@
> > +config DEBUG_VM_LAYOUT
> 
> I believe this could be enabled when CONFIG_DEBUG_VM=y without adding
> yet another architecture specific Kconfig option.

Oh yes, I will drop the newly added kconfig option in v2.

> --
> Sincerely yours,
> Mike.

Thanks for your comment!

- Yash