[PATCH 1/2] x86/microcode: Look for the initrd at the correct address on 32-bit

[PATCH 1/2] x86/microcode: Look for the initrd at the correct address on 32-bit

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Early during boot, the BSP finds the ramdisk's position from boot_params
but by the time the APs get to boot, the BSP has continued in the mean
time and has potentially managed to relocate that ramdisk.

And in that case, the APs need to find the ramdisk at its new position,
in *physical* memory as they're running before paging has been enabled.

Thus, get the updated physical location of the ramdisk which is in the
relocated_ramdisk variable.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/cpu/microcode/core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index e53d3c909840..9cb98ee103db 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -290,6 +290,17 @@ struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
 			return (struct cpio_data){ NULL, 0, "" };
 		if (initrd_start)
 			start = initrd_start;
+	} else {
+		/*
+		 * The picture with physical addresses is a bit different: we
+		 * need to get the *physical* address to which the ramdisk was
+		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
+		 * since we're running from physical addresses, we need to access
+		 * relocated_ramdisk through its *physical* address too.
+		 */
+		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
+		if (*rr)
+			start = *rr;
 	}
 
 	return find_cpio_data(path, (void *)start, size, NULL);
-- 
2.13.0

[PATCH 2/2] x86/microcode/intel: Save pointer to ucode patch for early AP loading

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Normally, when the initrd is gone, we can't search it for microcode
blobs to apply anymore. For that we need to stash away the patch in our
own storage.

And save_microcode_in_initrd_intel() looks like the proper place to
do that from. So in order for early loading to work, invalidate the
intel_ucode_patch pointer to the patch *before* scanning the initrd one
last time.

If the scanning code finds a microcode patch, it will assign that
pointer again, this time with our own storage's address.

This way, early microcode application during resume-from-RAM works too,
even after the initrd is long gone.

Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/x86/kernel/cpu/microcode/intel.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index f522415bf9e5..d525a0bd7d28 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -166,7 +166,7 @@ static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
 static void save_microcode_patch(void *data, unsigned int size)
 {
 	struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
-	struct ucode_patch *iter, *tmp, *p;
+	struct ucode_patch *iter, *tmp, *p = NULL;
 	bool prev_found = false;
 	unsigned int sig, pf;
 
@@ -202,6 +202,18 @@ static void save_microcode_patch(void *data, unsigned int size)
 		else
 			list_add_tail(&p->plist, &microcode_cache);
 	}
+
+	/*
+	 * Save for early loading. On 32-bit, that needs to be a physical
+	 * address as the APs are running from physical addresses, before
+	 * paging has been enabled.
+	 */
+	if (p) {
+		if (IS_ENABLED(CONFIG_X86_32))
+			intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
+		else
+			intel_ucode_patch = p->data;
+	}
 }
 
 static int microcode_sanity_check(void *mc, int print_err)
@@ -607,6 +619,14 @@ int __init save_microcode_in_initrd_intel(void)
 	struct ucode_cpu_info uci;
 	struct cpio_data cp;
 
+	/*
+	 * initrd is going away, clear patch ptr. We will scan the microcode one
+	 * last time before jettisoning and save a patch, if found. Then we will
+	 * update that pointer too, with a stable patch address to use when
+	 * resuming the cores.
+	 */
+	intel_ucode_patch = NULL;
+
 	if (!load_builtin_intel_microcode(&cp))
 		cp = find_microcode_in_initrd(ucode_path, false);
 
@@ -619,9 +639,6 @@ int __init save_microcode_in_initrd_intel(void)
 
 	show_saved_mc();
 
-	/* initrd is going away, clear patch ptr. */
-	intel_ucode_patch = NULL;
-
 	return 0;
 }
 
-- 
2.13.0

[tip:x86/microcode] x86/microcode/intel: Save pointer to ucode patch for early AP loading

[tip-bot for Borislav Petkov]

Commit-ID:  bd20733045d5db55515442d828376a3a71d6be48
Gitweb:     http://git.kernel.org/tip/bd20733045d5db55515442d828376a3a71d6be48
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Wed, 14 Jun 2017 16:06:26 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 20 Jun 2017 12:54:25 +0200

x86/microcode/intel: Save pointer to ucode patch for early AP loading

Normally, when the initrd is gone, we can't search it for microcode
blobs to apply anymore. For that we need to stash away the patch in our
own storage.

And save_microcode_in_initrd_intel() looks like the proper place to
do that from. So in order for early loading to work, invalidate the
intel_ucode_patch pointer to the patch *before* scanning the initrd one
last time.

If the scanning code finds a microcode patch, it will assign that
pointer again, this time with our own storage's address.

This way, early microcode application during resume-from-RAM works too,
even after the initrd is long gone.

Tested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170614140626.4462-2-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/cpu/microcode/intel.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index f522415..d525a0b 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -166,7 +166,7 @@ static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
 static void save_microcode_patch(void *data, unsigned int size)
 {
 	struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
-	struct ucode_patch *iter, *tmp, *p;
+	struct ucode_patch *iter, *tmp, *p = NULL;
 	bool prev_found = false;
 	unsigned int sig, pf;
 
@@ -202,6 +202,18 @@ static void save_microcode_patch(void *data, unsigned int size)
 		else
 			list_add_tail(&p->plist, &microcode_cache);
 	}
+
+	/*
+	 * Save for early loading. On 32-bit, that needs to be a physical
+	 * address as the APs are running from physical addresses, before
+	 * paging has been enabled.
+	 */
+	if (p) {
+		if (IS_ENABLED(CONFIG_X86_32))
+			intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
+		else
+			intel_ucode_patch = p->data;
+	}
 }
 
 static int microcode_sanity_check(void *mc, int print_err)
@@ -607,6 +619,14 @@ int __init save_microcode_in_initrd_intel(void)
 	struct ucode_cpu_info uci;
 	struct cpio_data cp;
 
+	/*
+	 * initrd is going away, clear patch ptr. We will scan the microcode one
+	 * last time before jettisoning and save a patch, if found. Then we will
+	 * update that pointer too, with a stable patch address to use when
+	 * resuming the cores.
+	 */
+	intel_ucode_patch = NULL;
+
 	if (!load_builtin_intel_microcode(&cp))
 		cp = find_microcode_in_initrd(ucode_path, false);
 
@@ -619,9 +639,6 @@ int __init save_microcode_in_initrd_intel(void)
 
 	show_saved_mc();
 
-	/* initrd is going away, clear patch ptr. */
-	intel_ucode_patch = NULL;
-
 	return 0;
 }
 

[tip:x86/microcode] x86/microcode: Look for the initrd at the correct address on 32-bit

[tip-bot for Borislav Petkov]

Commit-ID:  a3d98c9358e3be28282ff60dcca01dbc9f402f30
Gitweb:     http://git.kernel.org/tip/a3d98c9358e3be28282ff60dcca01dbc9f402f30
Author:     Borislav Petkov <bp@suse.de>
AuthorDate: Wed, 14 Jun 2017 16:06:25 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 20 Jun 2017 12:54:24 +0200

x86/microcode: Look for the initrd at the correct address on 32-bit

Early during boot, the BSP finds the ramdisk's position from boot_params
but by the time the APs get to boot, the BSP has continued in the mean
time and has potentially managed to relocate that ramdisk.

And in that case, the APs need to find the ramdisk at its new position,
in *physical* memory as they're running before paging has been enabled.

Thus, get the updated physical location of the ramdisk which is in the
relocated_ramdisk variable.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170614140626.4462-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/cpu/microcode/core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index e53d3c9..9cb98ee 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -290,6 +290,17 @@ struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
 			return (struct cpio_data){ NULL, 0, "" };
 		if (initrd_start)
 			start = initrd_start;
+	} else {
+		/*
+		 * The picture with physical addresses is a bit different: we
+		 * need to get the *physical* address to which the ramdisk was
+		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
+		 * since we're running from physical addresses, we need to access
+		 * relocated_ramdisk through its *physical* address too.
+		 */
+		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
+		if (*rr)
+			start = *rr;
 	}
 
 	return find_cpio_data(path, (void *)start, size, NULL);