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Message-ID: <AF233D1473C1364ABD51D28909A1B1B7326E3282@PGSMSX105.gar.corp.intel.com>
Date: Fri, 9 Jan 2015 01:00:17 +0000
From: "Ong, Boon Leong" <boon.leong.ong@...el.com>
To: Bryan O'Donoghue <pure.logic@...us-software.ie>
CC: "tglx@...utronix.de" <tglx@...utronix.de>,
"mingo@...hat.com" <mingo@...hat.com>,
"hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>,
"dvhart@...radead.org" <dvhart@...radead.org>,
"platform-driver-x86@...r.kernel.org"
<platform-driver-x86@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"andy.shevchenko@...il.com" <andy.shevchenko@...il.com>
Subject: RE: [PATCH 2/2] platform/x86: Add Intel Galileo platform specific
setup
>Subject: [PATCH 2/2] platform/x86: Add Intel Galileo platform specific setup
>
[snippet removed]
>Since the Quark EFI bringup code configures the system to reset on an IMR
Typo: bring-up
>violation, this means that common operations such as mouting an SD based root
Typo: mounting
[snippet removed]
>+config INTEL_GALILEO
>+ bool "Intel Galileo Platform Support"
>+ depends on X86_32 && PCI
>+ select IOSF_MBI
>+ select IMR
>+ ---help---
>+ Intel Galileo platform support. This code is used to tear-down
>+ BIOS and Grub Isolated Memory Regions used during bootup.
Missing dash. Should be "boot-up".
[snippet removed]
>diff --git a/drivers/platform/x86/intel_galileo.c
>b/drivers/platform/x86/intel_galileo.c
>new file mode 100644
>index 0000000..2a555aa
>--- /dev/null
>+++ b/drivers/platform/x86/intel_galileo.c
>@@ -0,0 +1,175 @@
>+/*
>+ * intel_galileo.c - Intel Galileo platform support.
>+ *
>+ * Copyright(c) 2013 Intel Corporation.
>+ * Copyright(c) 2014 Bryan O'Donoghue <pure.logic@...us-software.ie>
>+ *
>+ * This platform code provides an entry point to do Galileo specific
>+ * setup. Critically IMRs are policed to ensure the EFI provided memory
Critically --> Critical
>+ * map informing the kernel of it's available memory is consistent with
It's --> its
[snippet removed]
>+
>+enum {
>+ GALILEO_UNKNOWN = 0,
>+ GALILEO_QRK_GEN1,
>+ GALILEO_QRK_GEN2,
>+};
Suggest to drop QRK to kill confusion that it is Quark Gen 1 & 2.
[snippet removed]
>+#ifdef DEBUG
>+#define SANITY "IMR : sanity error "
>+
>+/**
Per coding style, please just use /* and kill the extra * above and below.
>+ * intel_galileo_imr_sanity
>+ * Verify IMR sanity with some simple tests to verify
>+ * overlap, zero sized allocations
>+ *
>+ * @base: Physical base address of the kernel text section
>+ * @size: Extent of kernel memory to be covered from &_text to
>+&_sinittext
>+ * @return: none
>+ */
>+static void __init
>+intel_galileo_imr_sanity(unsigned long base, unsigned long size) {
>+ /* Test zero zero */
>+ if (imr_add(0, 0, 0, 0, true) == 0)
>+ pr_err(SANITY "zero sized IMR @ 0x00000000\n");
A side-discussion on imr_add():
I would think that we should allow 1KiB IMR setting. Current imr_add() logic
is prohibiting it. So, the 'size' input should be at least 1KiB and imr_add()
internal logic will adjust 'hi' by -1KiB. Please consider ..
>+
>+ /* Test overlap */
>+ if (imr_add(base, size, IMR_NON_SMM, IMR_NON_SMM, true) == 0)
>+ pr_err(SANITY "overlapped IMR @ (0x%08lx - 0x%08lx)\n",
>+ base, base + size);
>+
>+ /* Try overlap - IMR_ALIGN */
>+ base = base + size - IMR_ALIGN;
>+ if (imr_add(base, size, IMR_NON_SMM, IMR_NON_SMM, true) == 0)
>+ pr_err(SANITY "overlapped IMR @ (0x%08lx - 0x%08lx)\n",
>+ base, base + size);
>+}
>+#endif
>+
>+/**
>+ * intel_galileo_imr_init
>+ *
>+ * Tear down IMRs used during bootup. BIOS and Grub
boot-up.
>+ * both setup IMRs around compressed kernel, initrd memory
>+ * that need to be removed before the kernel hands out one
>+ * of the IMR encased addresses to a downstream DMA agent
>+ * such as the SD or Ethernet. IMRs on Galileo are setup to
>+ * immediately reset the system on violation - so if you're
>+ * running a root filesystem from SD - you'll need the IMRs
>+ * torn down or you'll find seemingly random resets when using
>+ * your filesystem.
>+ */
>+static void __init intel_galileo_imr_init(void) {
>+ unsigned long base = virt_to_phys(&_text);
>+ unsigned long size = virt_to_phys(&_sinittext) - base - IMR_ALIGN;
>+ int i, ret;
>+
>+ /* Tear down all existing unlocked IMRs */
>+ for (i = 0; i <= QUARK_X1000_IMR_NUM; i++)
>+ imr_del(i, 0, 0);
>+
>+ /*
>+ * Setup an IMR around the physical extent of the kernel
>+ * Non-SMM mode core read/write from/to kernel physical region.
>+ * IMR locked.
>+ */
>+ ret = imr_add(base, size, IMR_NON_SMM, IMR_NON_SMM, true);
>+ if (ret)
>+ pr_err("Unable to setup IMR for kernel: (%p - %p)\n",
>+ &_text, &__init_begin);
>+ else
>+ pr_info("IMR protect kernel memory: %ldk (%p - %p)\n",
>+ size >> 10, &_text, &__init_begin);
Perhaps we want to be consistent between using __init_begin & _sinittext?
>+#ifdef DEBUG
>+ intel_galileo_imr_sanity(base, size);
>+#endif
>+}
>+
>+/**
>+ * intel_galileo_init
>+ *
>+ * Identify a Galileo Gen1 or Gen2. If found run code to sanitise the
>+ * kernel memory space of IMRs that are inconsistent with the EFI memory
>map.
>+ */
>+static int __init intel_galileo_init(void) {
>+ int ret = 0, type = GALILEO_UNKNOWN;
type is assigned to either GALILEO_GEN1|2 below anyway.
So, we don't need to declare to UNKNOWN?
[snippet removed]
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