| Message ID | 20240409211351.234897475@goodmis.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | pstore/mm/x86: Add wildcard memmap to map pstore consistently | expand |
On Tue, Apr 09, 2024 at 05:02:56PM -0400, Steven Rostedt wrote: > From: "Steven Rostedt (Google)" <rostedt@goodmis.org> > > Add a method to find a region specified by memmap=nn*align:name for > ramoops. Adding a kernel command line parameter: > > memmap=12M*4096:oops ramoops.mem_name=oops > > Will use the size and location defined by the memmap parameter where it > finds the memory and labels it "oops". The "oops" in the ramoops option > is used to search for it. > > This allows for arbitrary RAM to be used for ramoops if it is known that > the memory is not cleared on kernel crashes or soft reboots. > > Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> > --- > fs/pstore/ram.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c > index b1a455f42e93..c200388399fb 100644 > --- a/fs/pstore/ram.c > +++ b/fs/pstore/ram.c > @@ -50,6 +50,11 @@ module_param_hw(mem_address, ullong, other, 0400); > MODULE_PARM_DESC(mem_address, > "start of reserved RAM used to store oops/panic logs"); > > +static char *mem_name; > +module_param_named(mem_name, mem_name, charp, 0400); > +MODULE_PARM_DESC(mem_name, > + "name of kernel param that holds addr (builtin only)"); > + > static ulong mem_size; > module_param(mem_size, ulong, 0400); > MODULE_PARM_DESC(mem_size, > @@ -914,6 +919,19 @@ static void __init ramoops_register_dummy(void) > { > struct ramoops_platform_data pdata; > > +#ifndef MODULE > + /* Only allowed when builtin */ Why only when builtin? > + if (mem_name) { > + u64 start; > + u64 size; > + > + if (memmap_named(mem_name, &start, &size)) { > + mem_address = start; > + mem_size = size; > + } > + } > +#endif Otherwise this looks good, though I'd prefer some comments about what's happening here. (And in retrospect, separately, I probably need to rename "dummy" to "commandline" or something, since it's gathering valid settings here...)
On Tue, 9 Apr 2024 15:18:45 -0700 Kees Cook <keescook@chromium.org> wrote: > > @@ -914,6 +919,19 @@ static void __init ramoops_register_dummy(void) > > { > > struct ramoops_platform_data pdata; > > > > +#ifndef MODULE > > + /* Only allowed when builtin */ > > Why only when builtin? Well, because the memory table that maps the found physical memory to a lable is marked as __initdata, and will not be available after boot. If you wanted it for a module, you would need some builtin code to find it. > > > + if (mem_name) { > > + u64 start; > > + u64 size; > > + > > + if (memmap_named(mem_name, &start, &size)) { > > + mem_address = start; > > + mem_size = size; > > + } > > + } > > +#endif > > Otherwise this looks good, though I'd prefer some comments about what's > happening here. > > (And in retrospect, separately, I probably need to rename "dummy" to > "commandline" or something, since it's gathering valid settings here...) Yeah, that was a bit confusing. I kept thinking "is this function stable?". -- Steve
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index b1a455f42e93..c200388399fb 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -50,6 +50,11 @@ module_param_hw(mem_address, ullong, other, 0400); MODULE_PARM_DESC(mem_address, "start of reserved RAM used to store oops/panic logs"); +static char *mem_name; +module_param_named(mem_name, mem_name, charp, 0400); +MODULE_PARM_DESC(mem_name, + "name of kernel param that holds addr (builtin only)"); + static ulong mem_size; module_param(mem_size, ulong, 0400); MODULE_PARM_DESC(mem_size, @@ -914,6 +919,19 @@ static void __init ramoops_register_dummy(void) { struct ramoops_platform_data pdata; +#ifndef MODULE + /* Only allowed when builtin */ + if (mem_name) { + u64 start; + u64 size; + + if (memmap_named(mem_name, &start, &size)) { + mem_address = start; + mem_size = size; + } + } +#endif + /* * Prepare a dummy platform data structure to carry the module * parameters. If mem_size isn't set, then there are no module