linux54/56/57-tkg: Add GCC10 early boot crash fix - odyssey edition reborn - to base patchset.

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit?id=f670269a42bfdd2c83a1118cc3d1b475547eac22

Fixes the main blocker in https://github.com/Frogging-Family/linux-tkg/issues/7

linux54-tkg/PKGBUILD

@@ -89,7 +89,7 @@ pkgname=("${pkgbase}" "${pkgbase}-headers")
 _basekernel=5.4
 _sub=40
 pkgver="${_basekernel}"."${_sub}"
-pkgrel=55
+pkgrel=56
 pkgdesc='Linux-tkg'
 arch=('x86_64') # no i686 in here
 url="http://www.kernel.org/"
@@ -131,7 +131,7 @@ sha256sums=('bf338980b1670bca287f9994b7441c2361907635879169c64ae78364efc5f491'
             '66a03c246037451a77b4d448565b1d7e9368270c7d02872fbd0b5d024ed0a997'
             '31dc68e84aecfb7d069efb1305049122c65694676be8b955634abcf0675922a2'
             'd02bf5ca08fd610394b9d3a0c3b176d74af206f897dee826e5cbaec97bb4a4aa'
-            '55db7c30c6d5e7d88cf38a4c757e447faf11a7440afbc081c3da12757073cca7'
+            '10b3cb5c160abe6609ddb472c4012f1e473154ab8edaa680418d9615548a303c'
             '7058e57fd68367b029adc77f2a82928f1433daaf02c8c279cb2d13556c8804d7'
             'c605f638d74c61861ebdc36ebd4cb8b6475eae2f6273e1ccb2bbb3e10a2ec3fe'
             'bc69d6e5ee8172b0242c8fa72d13cfe2b8d2b6601468836908a7dfe8b78a3bbb'

linux54-tkg/linux54-tkg-patches/0003-glitched-base.patch

@@ -5197,3 +5197,129 @@ index a2adf95b3f9c..e804d9f7583a 100644
  
  int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
  			pgoff_t offset, unsigned long nr_to_read);
+
+rom f670269a42bfdd2c83a1118cc3d1b475547eac22 Mon Sep 17 00:00:00 2001
+From: Borislav Petkov <bp@suse.de>
+Date: Wed, 22 Apr 2020 18:11:30 +0200
+Subject: x86: Fix early boot crash on gcc-10, next try
+
+... or the odyssey of trying to disable the stack protector for the
+function which generates the stack canary value.
+
+The whole story started with Sergei reporting a boot crash with a kernel
+built with gcc-10:
+
+  Kernel panic — not syncing: stack-protector: Kernel stack is corrupted in: start_secondary
+  CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc5—00235—gfffb08b37df9 #139
+  Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M—D3H, BIOS F12 11/14/2013
+  Call Trace:
+    dump_stack
+    panic
+    ? start_secondary
+    __stack_chk_fail
+    start_secondary
+    secondary_startup_64
+  -—-[ end Kernel panic — not syncing: stack—protector: Kernel stack is corrupted in: start_secondary
+
+This happens because gcc-10 tail-call optimizes the last function call
+in start_secondary() - cpu_startup_entry() - and thus emits a stack
+canary check which fails because the canary value changes after the
+boot_init_stack_canary() call.
+
+To fix that, the initial attempt was to mark the one function which
+generates the stack canary with:
+
+  __attribute__((optimize("-fno-stack-protector"))) ... start_secondary(void *unused)
+
+however, using the optimize attribute doesn't work cumulatively
+as the attribute does not add to but rather replaces previously
+supplied optimization options - roughly all -fxxx options.
+
+The key one among them being -fno-omit-frame-pointer and thus leading to
+not present frame pointer - frame pointer which the kernel needs.
+
+The next attempt to prevent compilers from tail-call optimizing
+the last function call cpu_startup_entry(), shy of carving out
+start_secondary() into a separate compilation unit and building it with
+ -fno-stack-protector, is this one.
+
+The current solution is short and sweet, and reportedly, is supported by
+both compilers so let's see how far we'll get this time.
+
+Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
+Reviewed-by: Kees Cook <keescook@chromium.org>
+Link: https://lkml.kernel.org/r/20200314164451.346497-1-slyfox@gentoo.org
+---
+ arch/x86/include/asm/stackprotector.h | 7 ++++++-
+ arch/x86/kernel/smpboot.c             | 8 ++++++++
+ arch/x86/xen/smp_pv.c                 | 1 +
+ include/linux/compiler.h              | 6 ++++++
+ 4 files changed, 21 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
+index 91e29b6a86a5..9804a7957f4e 100644
+--- a/arch/x86/include/asm/stackprotector.h
++++ b/arch/x86/include/asm/stackprotector.h
+@@ -55,8 +55,13 @@
+ /*
+  * Initialize the stackprotector canary value.
+  *
+- * NOTE: this must only be called from functions that never return,
++ * NOTE: this must only be called from functions that never return
+  * and it must always be inlined.
++ *
++ * In addition, it should be called from a compilation unit for which
++ * stack protector is disabled. Alternatively, the caller should not end
++ * with a function call which gets tail-call optimized as that would
++ * lead to checking a modified canary value.
+  */
+ static __always_inline void boot_init_stack_canary(void)
+ {
+diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
+index fe3ab9632f3b..4f275ac7830b 100644
+--- a/arch/x86/kernel/smpboot.c
++++ b/arch/x86/kernel/smpboot.c
+@@ -266,6 +266,14 @@ static void notrace start_secondary(void *unused)
+ 
+ 	wmb();
+ 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
++
++	/*
++	 * Prevent tail call to cpu_startup_entry() because the stack protector
++	 * guard has been changed a couple of function calls up, in
++	 * boot_init_stack_canary() and must not be checked before tail calling
++	 * another function.
++	 */
++	prevent_tail_call_optimization();
+ }
+ 
+ /**
+diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
+index 8fb8a50a28b4..f2adb63b2d7c 100644
+--- a/arch/x86/xen/smp_pv.c
++++ b/arch/x86/xen/smp_pv.c
+@@ -93,6 +93,7 @@ asmlinkage __visible void cpu_bringup_and_idle(void)
+ 	cpu_bringup();
+ 	boot_init_stack_canary();
+ 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
++	prevent_tail_call_optimization();
+ }
+ 
+ void xen_smp_intr_free_pv(unsigned int cpu)
+diff --git a/include/linux/compiler.h b/include/linux/compiler.h
+index 034b0a644efc..732754d96039 100644
+--- a/include/linux/compiler.h
++++ b/include/linux/compiler.h
+@@ -356,4 +356,10 @@ static inline void *offset_to_ptr(const int *off)
+ /* &a[0] degrades to a pointer: a different type from an array */
+ #define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+ 
++/*
++ * This is needed in functions which generate the stack canary, see
++ * arch/x86/kernel/smpboot.c::start_secondary() for an example.
++ */
++#define prevent_tail_call_optimization()	asm("")
++
+ #endif /* __LINUX_COMPILER_H */

linux56-tkg/PKGBUILD

@@ -89,7 +89,7 @@ pkgname=("${pkgbase}" "${pkgbase}-headers")
 _basekernel=5.6
 _sub=12
 pkgver="${_basekernel}"."${_sub}"
-pkgrel=26
+pkgrel=27
 pkgdesc='Linux-tkg'
 arch=('x86_64') # no i686 in here
 url="http://www.kernel.org/"
@@ -133,7 +133,7 @@ sha256sums=('e342b04a2aa63808ea0ef1baab28fc520bd031ef8cf93d9ee4a31d4058fcb622'
             '66a03c246037451a77b4d448565b1d7e9368270c7d02872fbd0b5d024ed0a997'
             '31dc68e84aecfb7d069efb1305049122c65694676be8b955634abcf0675922a2'
             'd02bf5ca08fd610394b9d3a0c3b176d74af206f897dee826e5cbaec97bb4a4aa'
-            'a00a68f3689e187011d468e7112e95f7a525cc9e9369a106f02894ff37375ded'
+            '5987b3bd713d10fcd3c624785a1d0a8116325afab3e3752da6d4b1075b1a38d4'
             '7058e57fd68367b029adc77f2a82928f1433daaf02c8c279cb2d13556c8804d7'
             'c605f638d74c61861ebdc36ebd4cb8b6475eae2f6273e1ccb2bbb3e10a2ec3fe'
             'bc69d6e5ee8172b0242c8fa72d13cfe2b8d2b6601468836908a7dfe8b78a3bbb'

linux56-tkg/linux56-tkg-patches/0003-glitched-base.patch

@@ -1745,3 +1745,129 @@ diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
  
  	/* Update ghc->generation before performing any error checks. */
  	ghc->generation = slots->generation;
+
+rom f670269a42bfdd2c83a1118cc3d1b475547eac22 Mon Sep 17 00:00:00 2001
+From: Borislav Petkov <bp@suse.de>
+Date: Wed, 22 Apr 2020 18:11:30 +0200
+Subject: x86: Fix early boot crash on gcc-10, next try
+
+... or the odyssey of trying to disable the stack protector for the
+function which generates the stack canary value.
+
+The whole story started with Sergei reporting a boot crash with a kernel
+built with gcc-10:
+
+  Kernel panic — not syncing: stack-protector: Kernel stack is corrupted in: start_secondary
+  CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc5—00235—gfffb08b37df9 #139
+  Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M—D3H, BIOS F12 11/14/2013
+  Call Trace:
+    dump_stack
+    panic
+    ? start_secondary
+    __stack_chk_fail
+    start_secondary
+    secondary_startup_64
+  -—-[ end Kernel panic — not syncing: stack—protector: Kernel stack is corrupted in: start_secondary
+
+This happens because gcc-10 tail-call optimizes the last function call
+in start_secondary() - cpu_startup_entry() - and thus emits a stack
+canary check which fails because the canary value changes after the
+boot_init_stack_canary() call.
+
+To fix that, the initial attempt was to mark the one function which
+generates the stack canary with:
+
+  __attribute__((optimize("-fno-stack-protector"))) ... start_secondary(void *unused)
+
+however, using the optimize attribute doesn't work cumulatively
+as the attribute does not add to but rather replaces previously
+supplied optimization options - roughly all -fxxx options.
+
+The key one among them being -fno-omit-frame-pointer and thus leading to
+not present frame pointer - frame pointer which the kernel needs.
+
+The next attempt to prevent compilers from tail-call optimizing
+the last function call cpu_startup_entry(), shy of carving out
+start_secondary() into a separate compilation unit and building it with
+ -fno-stack-protector, is this one.
+
+The current solution is short and sweet, and reportedly, is supported by
+both compilers so let's see how far we'll get this time.
+
+Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
+Reviewed-by: Kees Cook <keescook@chromium.org>
+Link: https://lkml.kernel.org/r/20200314164451.346497-1-slyfox@gentoo.org
+---
+ arch/x86/include/asm/stackprotector.h | 7 ++++++-
+ arch/x86/kernel/smpboot.c             | 8 ++++++++
+ arch/x86/xen/smp_pv.c                 | 1 +
+ include/linux/compiler.h              | 6 ++++++
+ 4 files changed, 21 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
+index 91e29b6a86a5..9804a7957f4e 100644
+--- a/arch/x86/include/asm/stackprotector.h
++++ b/arch/x86/include/asm/stackprotector.h
+@@ -55,8 +55,13 @@
+ /*
+  * Initialize the stackprotector canary value.
+  *
+- * NOTE: this must only be called from functions that never return,
++ * NOTE: this must only be called from functions that never return
+  * and it must always be inlined.
++ *
++ * In addition, it should be called from a compilation unit for which
++ * stack protector is disabled. Alternatively, the caller should not end
++ * with a function call which gets tail-call optimized as that would
++ * lead to checking a modified canary value.
+  */
+ static __always_inline void boot_init_stack_canary(void)
+ {
+diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
+index fe3ab9632f3b..4f275ac7830b 100644
+--- a/arch/x86/kernel/smpboot.c
++++ b/arch/x86/kernel/smpboot.c
+@@ -266,6 +266,14 @@ static void notrace start_secondary(void *unused)
+ 
+ 	wmb();
+ 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
++
++	/*
++	 * Prevent tail call to cpu_startup_entry() because the stack protector
++	 * guard has been changed a couple of function calls up, in
++	 * boot_init_stack_canary() and must not be checked before tail calling
++	 * another function.
++	 */
++	prevent_tail_call_optimization();
+ }
+ 
+ /**
+diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
+index 8fb8a50a28b4..f2adb63b2d7c 100644
+--- a/arch/x86/xen/smp_pv.c
++++ b/arch/x86/xen/smp_pv.c
+@@ -93,6 +93,7 @@ asmlinkage __visible void cpu_bringup_and_idle(void)
+ 	cpu_bringup();
+ 	boot_init_stack_canary();
+ 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
++	prevent_tail_call_optimization();
+ }
+ 
+ void xen_smp_intr_free_pv(unsigned int cpu)
+diff --git a/include/linux/compiler.h b/include/linux/compiler.h
+index 034b0a644efc..732754d96039 100644
+--- a/include/linux/compiler.h
++++ b/include/linux/compiler.h
+@@ -356,4 +356,10 @@ static inline void *offset_to_ptr(const int *off)
+ /* &a[0] degrades to a pointer: a different type from an array */
+ #define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+ 
++/*
++ * This is needed in functions which generate the stack canary, see
++ * arch/x86/kernel/smpboot.c::start_secondary() for an example.
++ */
++#define prevent_tail_call_optimization()	asm("")
++
+ #endif /* __LINUX_COMPILER_H */

linux57-rc-tkg/PKGBUILD

@@ -126,7 +126,7 @@ sha256sums=('0bed1c1d79abff19045870e93bdf8930e848502d25464ff01fd3b8d01de88a41'
             '66a03c246037451a77b4d448565b1d7e9368270c7d02872fbd0b5d024ed0a997'
             '31dc68e84aecfb7d069efb1305049122c65694676be8b955634abcf0675922a2'
             'd02bf5ca08fd610394b9d3a0c3b176d74af206f897dee826e5cbaec97bb4a4aa'
-            '8352d688733b23472d10aa2fec3f604606fdeb957bc35f4851831a9b624556b8'
+            'b641a948e9f98a2cdb4ae7f541a1376ebd390ff3404affe611d6a10e2a98e0ab'
             '7058e57fd68367b029adc77f2a82928f1433daaf02c8c279cb2d13556c8804d7'
             '62496f9ca788996181ef145f96ad26291282fcc3fb95cdc04080dcf84365be33'
             '7fd8e776209dac98627453fda754bdf9aff4a09f27cb0b3766d7983612eb3c74'

linux57-rc-tkg/linux57-tkg-patches/0003-glitched-base.patch

@@ -1444,3 +1444,129 @@ index d2fa3e9ccd97c..bd10cb02fc0ff 100644
  	if (!strcmp(str, "force"))
  		force_load = 1;
  	if (!strcmp(str, "hwp_only"))
+
+From f670269a42bfdd2c83a1118cc3d1b475547eac22 Mon Sep 17 00:00:00 2001
+From: Borislav Petkov <bp@suse.de>
+Date: Wed, 22 Apr 2020 18:11:30 +0200
+Subject: x86: Fix early boot crash on gcc-10, next try
+
+... or the odyssey of trying to disable the stack protector for the
+function which generates the stack canary value.
+
+The whole story started with Sergei reporting a boot crash with a kernel
+built with gcc-10:
+
+  Kernel panic — not syncing: stack-protector: Kernel stack is corrupted in: start_secondary
+  CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc5—00235—gfffb08b37df9 #139
+  Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M—D3H, BIOS F12 11/14/2013
+  Call Trace:
+    dump_stack
+    panic
+    ? start_secondary
+    __stack_chk_fail
+    start_secondary
+    secondary_startup_64
+  -—-[ end Kernel panic — not syncing: stack—protector: Kernel stack is corrupted in: start_secondary
+
+This happens because gcc-10 tail-call optimizes the last function call
+in start_secondary() - cpu_startup_entry() - and thus emits a stack
+canary check which fails because the canary value changes after the
+boot_init_stack_canary() call.
+
+To fix that, the initial attempt was to mark the one function which
+generates the stack canary with:
+
+  __attribute__((optimize("-fno-stack-protector"))) ... start_secondary(void *unused)
+
+however, using the optimize attribute doesn't work cumulatively
+as the attribute does not add to but rather replaces previously
+supplied optimization options - roughly all -fxxx options.
+
+The key one among them being -fno-omit-frame-pointer and thus leading to
+not present frame pointer - frame pointer which the kernel needs.
+
+The next attempt to prevent compilers from tail-call optimizing
+the last function call cpu_startup_entry(), shy of carving out
+start_secondary() into a separate compilation unit and building it with
+ -fno-stack-protector, is this one.
+
+The current solution is short and sweet, and reportedly, is supported by
+both compilers so let's see how far we'll get this time.
+
+Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
+Reviewed-by: Kees Cook <keescook@chromium.org>
+Link: https://lkml.kernel.org/r/20200314164451.346497-1-slyfox@gentoo.org
+---
+ arch/x86/include/asm/stackprotector.h | 7 ++++++-
+ arch/x86/kernel/smpboot.c             | 8 ++++++++
+ arch/x86/xen/smp_pv.c                 | 1 +
+ include/linux/compiler.h              | 6 ++++++
+ 4 files changed, 21 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
+index 91e29b6a86a5..9804a7957f4e 100644
+--- a/arch/x86/include/asm/stackprotector.h
++++ b/arch/x86/include/asm/stackprotector.h
+@@ -55,8 +55,13 @@
+ /*
+  * Initialize the stackprotector canary value.
+  *
+- * NOTE: this must only be called from functions that never return,
++ * NOTE: this must only be called from functions that never return
+  * and it must always be inlined.
++ *
++ * In addition, it should be called from a compilation unit for which
++ * stack protector is disabled. Alternatively, the caller should not end
++ * with a function call which gets tail-call optimized as that would
++ * lead to checking a modified canary value.
+  */
+ static __always_inline void boot_init_stack_canary(void)
+ {
+diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
+index fe3ab9632f3b..4f275ac7830b 100644
+--- a/arch/x86/kernel/smpboot.c
++++ b/arch/x86/kernel/smpboot.c
+@@ -266,6 +266,14 @@ static void notrace start_secondary(void *unused)
+ 
+ 	wmb();
+ 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
++
++	/*
++	 * Prevent tail call to cpu_startup_entry() because the stack protector
++	 * guard has been changed a couple of function calls up, in
++	 * boot_init_stack_canary() and must not be checked before tail calling
++	 * another function.
++	 */
++	prevent_tail_call_optimization();
+ }
+ 
+ /**
+diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
+index 8fb8a50a28b4..f2adb63b2d7c 100644
+--- a/arch/x86/xen/smp_pv.c
++++ b/arch/x86/xen/smp_pv.c
+@@ -93,6 +93,7 @@ asmlinkage __visible void cpu_bringup_and_idle(void)
+ 	cpu_bringup();
+ 	boot_init_stack_canary();
+ 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
++	prevent_tail_call_optimization();
+ }
+ 
+ void xen_smp_intr_free_pv(unsigned int cpu)
+diff --git a/include/linux/compiler.h b/include/linux/compiler.h
+index 034b0a644efc..732754d96039 100644
+--- a/include/linux/compiler.h
++++ b/include/linux/compiler.h
+@@ -356,4 +356,10 @@ static inline void *offset_to_ptr(const int *off)
+ /* &a[0] degrades to a pointer: a different type from an array */
+ #define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+ 
++/*
++ * This is needed in functions which generate the stack canary, see
++ * arch/x86/kernel/smpboot.c::start_secondary() for an example.
++ */
++#define prevent_tail_call_optimization()	asm("")
++
+ #endif /* __LINUX_COMPILER_H */