linux-dev/arch/x86/kernel/cpu/mce/inject.c, branch linus/master

x86/mce/inject: Avoid out-of-bounds write when setting flags

2021-12-28T10:45:36Z

A contrived zero-length write, for example, by using write(2): ... ret = write(fd, str, 0); ... to the "flags" file causes: BUG: KASAN: stack-out-of-bounds in flags_write Write of size 1 at addr ffff888019be7ddf by task writefile/3787 CPU: 4 PID: 3787 Comm: writefile Not tainted 5.16.0-rc7+ #12 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 due to accessing buf one char before its start. Prevent such out-of-bounds access. [ bp: Productize into a proper patch. Link below is the next best thing because the original mail didn't get archived on lore. ] Fixes: 0451d14d0561 ("EDAC, mce_amd_inj: Modify flags attribute to use string arguments") Signed-off-by: Zhang Zixun Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/linux-edac/YcnePfF1OOqoQwrX@zn.tnic/

x86/mce/inject: Set the valid bit in MCA_STATUS before error injection

2021-12-08T11:01:01Z

MCA handlers check the valid bit in each status register (MCA_STATUS[Val]) and continue processing the error only if the valid bit is set. Set the valid bit unconditionally in the corresponding MCA_STATUS register and correct any Val=0 injections made by the user as such errors will get ignored and such injections will be largely pointless. Signed-off-by: Smita Koralahalli Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20211104215846.254012-3-Smita.KoralahalliChannabasappa@amd.com

x86/mce/inject: Check if a bank is populated before injecting

2021-12-08T11:00:56Z

The MCA_IPID register uniquely identifies a bank's type on Scalable MCA (SMCA) systems. When an MCA bank is not populated, the MCA_IPID register will read as zero and writes to it will be ignored. On a hw-type error injection (injection which writes the actual MCA registers in an attempt to cause a real MCE) check the value of this register before trying to inject the error. Do not impose any limitations on a sw injection and allow the user to test out all the decoding paths without relying on the available hardware, as its purpose is to just test the code. [ bp: Heavily massage. ] Link: https://lkml.kernel.org/r/20211019233641.140275-2-Smita.KoralahalliChannabasappa@amd.com Signed-off-by: Smita Koralahalli Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20211104215846.254012-2-Smita.KoralahalliChannabasappa@amd.com

x86/mce/inject: Replace deprecated CPU-hotplug functions.

2021-08-10T12:46:27Z

The functions get_online_cpus() and put_online_cpus() have been deprecated during the CPU hotplug rework. They map directly to cpus_read_lock() and cpus_read_unlock(). Replace deprecated CPU-hotplug functions with the official version. The behavior remains unchanged. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210803141621.780504-10-bigeasy@linutronix.de

x86/mce/inject: Add IPID for injection too

2021-03-23T23:04:45Z

Add an injection file in order to specify the IPID too when injecting an error. One use case example is using the machinery to decode MCEs collected from other machines. Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210314201806.12798-1-bp@alien8.de

x86/CPU/AMD: Remove amd_get_nb_id()

2020-11-19T10:43:17Z

The Last Level Cache ID is returned by amd_get_nb_id(). In practice, this value is the same as the AMD NodeId for callers of this function. The NodeId is saved in struct cpuinfo_x86.cpu_die_id. Replace calls to amd_get_nb_id() with the logical CPU's cpu_die_id and remove the function. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20201109210659.754018-3-Yazen.Ghannam@amd.com

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59Z

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

x86/mce/inject: Fix a wrong assignment of i_mce.status

2020-06-15T11:38:55Z

The original code is a nop as i_mce.status is or'ed with part of itself, fix it. Fixes: a1300e505297 ("x86/ras/mce_amd_inj: Trigger deferred and thresholding errors interrupts") Signed-off-by: Zhenzhong Duan Signed-off-by: Borislav Petkov Acked-by: Yazen Ghannam Link: https://lkml.kernel.org/r/20200611023238.3830-1-zhenzhong.duan@gmail.com

x86/entry: Convert Machine Check to IDTENTRY_IST

2020-06-11T13:14:57Z

Convert #MC to IDTENTRY_MCE: - Implement the C entry points with DEFINE_IDTENTRY_MCE - Emit the ASM stub with DECLARE_IDTENTRY_MCE - Remove the ASM idtentry in 64bit - Remove the open coded ASM entry code in 32bit - Fixup the XEN/PV code - Remove the old prototypes - Remove the error code from *machine_check_vector() as it is always 0 and not used by any of the functions it can point to. Fixup all the functions as well. No functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135314.334980426@linutronix.de

x86/mce: Remove mce_inject_log() in favor of mce_log()

2019-12-17T09:26:41Z

The mutex in mce_inject_log() became unnecessary with commit 5de97c9f6d85 ("x86/mce: Factor out and deprecate the /dev/mcelog driver"), though the original reason for its presence only vanished with commit 7298f08ea887 ("x86/mcelog: Get rid of RCU remnants"). Drop the mutex. And as that makes mce_inject_log() identical to mce_log(), get rid of the former in favor of the latter. Signed-off-by: Jan H. Schönherr Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20191210000733.17979-7-jschoenh@amazon.de