kernel/linux.git, branch v3.2.98

Linux 3.2.98

2018-01-07T01:46:55+00:00

KPTI: Report when enabled

2018-01-07T01:46:54+00:00

Make sure dmesg reports when KPTI is enabled. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

KPTI: Rename to PAGE_TABLE_ISOLATION

2018-01-07T01:46:54+00:00

This renames CONFIG_KAISER to CONFIG_PAGE_TABLE_ISOLATION. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2] Signed-off-by: Ben Hutchings

x86/kaiser: Move feature detection up

2018-01-07T01:46:53+00:00

... before the first use of kaiser_enabled as otherwise funky things happen: about to get started... (XEN) d0v0 Unhandled page fault fault/trap [#14, ec=0000] (XEN) Pagetable walk from ffff88022a449090: (XEN) L4[0x110] = 0000000229e0e067 0000000000001e0e (XEN) L3[0x008] = 0000000000000000 ffffffffffffffff (XEN) domain_crash_sync called from entry.S: fault at ffff82d08033fd08 entry.o#create_bounce_frame+0x135/0x14d (XEN) Domain 0 (vcpu#0) crashed on cpu#0: (XEN) ----[ Xen-4.9.1_02-3.21 x86_64 debug=n Not tainted ]---- (XEN) CPU: 0 (XEN) RIP: e033:[] (XEN) RFLAGS: 0000000000000286 EM: 1 CONTEXT: pv guest (d0v0) Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

kaiser: disabled on Xen PV

2018-01-07T01:46:53+00:00

Kaiser cannot be used on paravirtualized MMUs (namely reading and writing CR3). This does not work with KAISER as the CR3 switch from and to user space PGD would require to map the whole XEN_PV machinery into both. More importantly, enabling KAISER on Xen PV doesn't make too much sense, as PV guests use distinct %cr3 values for kernel and user already. Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: use xen_pv_domain()] Signed-off-by: Ben Hutchings

x86/kaiser: Reenable PARAVIRT

2018-01-07T01:46:53+00:00

Now that the required bits have been addressed, reenable PARAVIRT. Signed-off-by: Borislav Petkov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

x86/paravirt: Dont patch flush_tlb_single

2018-01-07T01:46:53+00:00

commit a035795499ca1c2bd1928808d1a156eda1420383 upstream. native_flush_tlb_single() will be changed with the upcoming PAGE_TABLE_ISOLATION feature. This requires to have more code in there than INVLPG. Remove the paravirt patching for it. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Reviewed-by: Juergen Gross Acked-by: Peter Zijlstra Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Rik van Riel Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org Cc: michael.schwarz@iaik.tugraz.at Cc: moritz.lipp@iaik.tugraz.at Cc: richard.fellner@student.tugraz.at Link: https://lkml.kernel.org/r/20171204150606.828111617@linutronix.de Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

kaiser: kaiser_flush_tlb_on_return_to_user() check PCID

2018-01-07T01:46:53+00:00

Let kaiser_flush_tlb_on_return_to_user() do the X86_FEATURE_PCID check, instead of each caller doing it inline first: nobody needs to optimize for the noPCID case, it's clearer this way, and better suits later changes. Replace those no-op X86_CR3_PCID_KERN_FLUSH lines by a BUILD_BUG_ON() in load_new_mm_cr3(), in case something changes. (cherry picked from Change-Id: I9b528ed9d7c1ae4a3b4738c2894ee1740b6fb0b9) Signed-off-by: Hugh Dickins Signed-off-by: Ben Hutchings

kaiser: asm/tlbflush.h handle noPGE at lower level

2018-01-07T01:46:52+00:00

I found asm/tlbflush.h too twisty, and think it safer not to avoid __native_flush_tlb_global_irq_disabled() in the kaiser_enabled case, but instead let it handle kaiser_enabled along with cr3: it can just use __native_flush_tlb() for that, no harm in re-disabling preemption. (This is not the same change as Kirill and Dave have suggested for upstream, flipping PGE in cr4: that's neat, but needs a cpu_has_pge check; cr3 is enough for kaiser, and thought to be cheaper than cr4.) Also delete the X86_FEATURE_INVPCID invpcid_flush_all_nonglobals() preference from __native_flush_tlb(): unlike the invpcid_flush_all() preference in __native_flush_tlb_global(), it's not seen in upstream 4.14, and was recently reported to be surprisingly slow. (cherry picked from Change-Id: I0da819a797ff46bca6590040b6480178dff6ba1e) Signed-off-by: Hugh Dickins Signed-off-by: Ben Hutchings

kaiser: use ALTERNATIVE instead of x86_cr3_pcid_noflush

2018-01-07T01:46:52+00:00

Now that we're playing the ALTERNATIVE game, use that more efficient method: instead of user-mapping an extra page, and reading an extra cacheline each time for x86_cr3_pcid_noflush. Neel has found that __stringify(bts $X86_CR3_PCID_NOFLUSH_BIT, %rax) is a working substitute for the "bts $63, %rax" in these ALTERNATIVEs; but the one line with $63 in looks clearer, so let's stick with that. Worried about what happens with an ALTERNATIVE between the jump and jump label in another ALTERNATIVE? I was, but have checked the combinations in SWITCH_KERNEL_CR3_NO_STACK at entry_SYSCALL_64, and it does a good job. (cherry picked from Change-Id: I46d06167615aa8d628eed9972125ab2faca93f05) Signed-off-by: Hugh Dickins Signed-off-by: Ben Hutchings