powerpc: introduce ePAPR embedded hypervisor hcall interface

ePAPR hypervisors provide operating system services via a "hypercall"
interface.  The following steps need to be performed to make an hcall:

1. Load r11 with the hcall number
2. Load specific other registers with parameters
3. Issue instrucion "sc 1"
4. The return code is in r3
5. Other returned parameters are in other registers.

To provide this service to the kernel, these steps are wrapped in inline
assembly functions.  Standard ePAPR hcalls are in epapr_hcalls.h, and
Freescale extensions are in fsl_hcalls.h.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 502 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h
new file mode 100644
index 000000000000..f3b0c2cc9fea
--- /dev/null
+++ b/arch/powerpc/include/asm/epapr_hcalls.h
@@ -0,0 +1,502 @@
+/*
+ * ePAPR hcall interface
+ *
+ * Copyright 2008-2011 Freescale Semiconductor, Inc.
+ *
+ * Author: Timur Tabi <timur@freescale.com>
+ *
+ * This file is provided under a dual BSD/GPL license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Freescale Semiconductor nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL Freescale Semiconductor BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* A "hypercall" is an "sc 1" instruction.  This header file file provides C
+ * wrapper functions for the ePAPR hypervisor interface.  It is inteded
+ * for use by Linux device drivers and other operating systems.
+ *
+ * The hypercalls are implemented as inline assembly, rather than assembly
+ * language functions in a .S file, for optimization.  It allows
+ * the caller to issue the hypercall instruction directly, improving both
+ * performance and memory footprint.
+ */
+
+#ifndef _EPAPR_HCALLS_H
+#define _EPAPR_HCALLS_H
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <asm/byteorder.h>
+
+#define EV_BYTE_CHANNEL_SEND		1
+#define EV_BYTE_CHANNEL_RECEIVE		2
+#define EV_BYTE_CHANNEL_POLL		3
+#define EV_INT_SET_CONFIG		4
+#define EV_INT_GET_CONFIG		5
+#define EV_INT_SET_MASK			6
+#define EV_INT_GET_MASK			7
+#define EV_INT_IACK			9
+#define EV_INT_EOI			10
+#define EV_INT_SEND_IPI			11
+#define EV_INT_SET_TASK_PRIORITY	12
+#define EV_INT_GET_TASK_PRIORITY	13
+#define EV_DOORBELL_SEND		14
+#define EV_MSGSND			15
+#define EV_IDLE				16
+
+/* vendor ID: epapr */
+#define EV_LOCAL_VENDOR_ID		0	/* for private use */
+#define EV_EPAPR_VENDOR_ID		1
+#define EV_FSL_VENDOR_ID		2	/* Freescale Semiconductor */
+#define EV_IBM_VENDOR_ID		3	/* IBM */
+#define EV_GHS_VENDOR_ID		4	/* Green Hills Software */
+#define EV_ENEA_VENDOR_ID		5	/* Enea */
+#define EV_WR_VENDOR_ID			6	/* Wind River Systems */
+#define EV_AMCC_VENDOR_ID		7	/* Applied Micro Circuits */
+#define EV_KVM_VENDOR_ID		42	/* KVM */
+
+/* The max number of bytes that a byte channel can send or receive per call */
+#define EV_BYTE_CHANNEL_MAX_BYTES	16
+
+
+#define _EV_HCALL_TOKEN(id, num) (((id) << 16) | (num))
+#define EV_HCALL_TOKEN(hcall_num) _EV_HCALL_TOKEN(EV_EPAPR_VENDOR_ID, hcall_num)
+
+/* epapr error codes */
+#define EV_EPERM		1	/* Operation not permitted */
+#define EV_ENOENT		2	/*  Entry Not Found */
+#define EV_EIO			3	/* I/O error occured */
+#define EV_EAGAIN		4	/* The operation had insufficient
+					 * resources to complete and should be
+					 * retried
+					 */
+#define EV_ENOMEM		5	/* There was insufficient memory to
+					 * complete the operation */
+#define EV_EFAULT		6	/* Bad guest address */
+#define EV_ENODEV		7	/* No such device */
+#define EV_EINVAL		8	/* An argument supplied to the hcall
+					   was out of range or invalid */
+#define EV_INTERNAL		9	/* An internal error occured */
+#define EV_CONFIG		10	/* A configuration error was detected */
+#define EV_INVALID_STATE	11	/* The object is in an invalid state */
+#define EV_UNIMPLEMENTED	12	/* Unimplemented hypercall */
+#define EV_BUFFER_OVERFLOW	13	/* Caller-supplied buffer too small */
+
+/*
+ * Hypercall register clobber list
+ *
+ * These macros are used to define the list of clobbered registers during a
+ * hypercall.  Technically, registers r0 and r3-r12 are always clobbered,
+ * but the gcc inline assembly syntax does not allow us to specify registers
+ * on the clobber list that are also on the input/output list.  Therefore,
+ * the lists of clobbered registers depends on the number of register
+ * parmeters ("+r" and "=r") passed to the hypercall.
+ *
+ * Each assembly block should use one of the HCALL_CLOBBERSx macros.  As a
+ * general rule, 'x' is the number of parameters passed to the assembly
+ * block *except* for r11.
+ *
+ * If you're not sure, just use the smallest value of 'x' that does not
+ * generate a compilation error.  Because these are static inline functions,
+ * the compiler will only check the clobber list for a function if you
+ * compile code that calls that function.
+ *
+ * r3 and r11 are not included in any clobbers list because they are always
+ * listed as output registers.
+ *
+ * XER, CTR, and LR are currently listed as clobbers because it's uncertain
+ * whether they will be clobbered.
+ *
+ * Note that r11 can be used as an output parameter.
+*/
+
+/* List of common clobbered registers.  Do not use this macro. */
+#define EV_HCALL_CLOBBERS "r0", "r12", "xer", "ctr", "lr", "cc"
+
+#define EV_HCALL_CLOBBERS8 EV_HCALL_CLOBBERS
+#define EV_HCALL_CLOBBERS7 EV_HCALL_CLOBBERS8, "r10"
+#define EV_HCALL_CLOBBERS6 EV_HCALL_CLOBBERS7, "r9"
+#define EV_HCALL_CLOBBERS5 EV_HCALL_CLOBBERS6, "r8"
+#define EV_HCALL_CLOBBERS4 EV_HCALL_CLOBBERS5, "r7"
+#define EV_HCALL_CLOBBERS3 EV_HCALL_CLOBBERS4, "r6"
+#define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5"
+#define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4"
+
+
+/*
+ * We use "uintptr_t" to define a register because it's guaranteed to be a
+ * 32-bit integer on a 32-bit platform, and a 64-bit integer on a 64-bit
+ * platform.
+ *
+ * All registers are either input/output or output only.  Registers that are
+ * initialized before making the hypercall are input/output.  All
+ * input/output registers are represented with "+r".  Output-only registers
+ * are represented with "=r".  Do not specify any unused registers.  The
+ * clobber list will tell the compiler that the hypercall modifies those
+ * registers, which is good enough.
+ */
+
+/**
+ * ev_int_set_config - configure the specified interrupt
+ * @interrupt: the interrupt number
+ * @config: configuration for this interrupt
+ * @priority: interrupt priority
+ * @destination: destination CPU number
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_int_set_config(unsigned int interrupt,
+	uint32_t config, unsigned int priority, uint32_t destination)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+	register uintptr_t r5 __asm__("r5");
+	register uintptr_t r6 __asm__("r6");
+
+	r11 = EV_HCALL_TOKEN(EV_INT_SET_CONFIG);
+	r3  = interrupt;
+	r4  = config;
+	r5  = priority;
+	r6  = destination;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "+r" (r4), "+r" (r5), "+r" (r6)
+		: : EV_HCALL_CLOBBERS4
+	);
+
+	return r3;
+}
+
+/**
+ * ev_int_get_config - return the config of the specified interrupt
+ * @interrupt: the interrupt number
+ * @config: returned configuration for this interrupt
+ * @priority: returned interrupt priority
+ * @destination: returned destination CPU number
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_int_get_config(unsigned int interrupt,
+	uint32_t *config, unsigned int *priority, uint32_t *destination)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+	register uintptr_t r5 __asm__("r5");
+	register uintptr_t r6 __asm__("r6");
+
+	r11 = EV_HCALL_TOKEN(EV_INT_GET_CONFIG);
+	r3 = interrupt;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "=r" (r4), "=r" (r5), "=r" (r6)
+		: : EV_HCALL_CLOBBERS4
+	);
+
+	*config = r4;
+	*priority = r5;
+	*destination = r6;
+
+	return r3;
+}
+
+/**
+ * ev_int_set_mask - sets the mask for the specified interrupt source
+ * @interrupt: the interrupt number
+ * @mask: 0=enable interrupts, 1=disable interrupts
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_int_set_mask(unsigned int interrupt,
+	unsigned int mask)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+
+	r11 = EV_HCALL_TOKEN(EV_INT_SET_MASK);
+	r3 = interrupt;
+	r4 = mask;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "+r" (r4)
+		: : EV_HCALL_CLOBBERS2
+	);
+
+	return r3;
+}
+
+/**
+ * ev_int_get_mask - returns the mask for the specified interrupt source
+ * @interrupt: the interrupt number
+ * @mask: returned mask for this interrupt (0=enabled, 1=disabled)
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_int_get_mask(unsigned int interrupt,
+	unsigned int *mask)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+
+	r11 = EV_HCALL_TOKEN(EV_INT_GET_MASK);
+	r3 = interrupt;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "=r" (r4)
+		: : EV_HCALL_CLOBBERS2
+	);
+
+	*mask = r4;
+
+	return r3;
+}
+
+/**
+ * ev_int_eoi - signal the end of interrupt processing
+ * @interrupt: the interrupt number
+ *
+ * This function signals the end of processing for the the specified
+ * interrupt, which must be the interrupt currently in service. By
+ * definition, this is also the highest-priority interrupt.
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_int_eoi(unsigned int interrupt)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+
+	r11 = EV_HCALL_TOKEN(EV_INT_EOI);
+	r3 = interrupt;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3)
+		: : EV_HCALL_CLOBBERS1
+	);
+
+	return r3;
+}
+
+/**
+ * ev_byte_channel_send - send characters to a byte stream
+ * @handle: byte stream handle
+ * @count: (input) num of chars to send, (output) num chars sent
+ * @buffer: pointer to a 16-byte buffer
+ *
+ * @buffer must be at least 16 bytes long, because all 16 bytes will be
+ * read from memory into registers, even if count < 16.
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_byte_channel_send(unsigned int handle,
+	unsigned int *count, const char buffer[EV_BYTE_CHANNEL_MAX_BYTES])
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+	register uintptr_t r5 __asm__("r5");
+	register uintptr_t r6 __asm__("r6");
+	register uintptr_t r7 __asm__("r7");
+	register uintptr_t r8 __asm__("r8");
+	const uint32_t *p = (const uint32_t *) buffer;
+
+	r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_SEND);
+	r3 = handle;
+	r4 = *count;
+	r5 = be32_to_cpu(p[0]);
+	r6 = be32_to_cpu(p[1]);
+	r7 = be32_to_cpu(p[2]);
+	r8 = be32_to_cpu(p[3]);
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3),
+		  "+r" (r4), "+r" (r5), "+r" (r6), "+r" (r7), "+r" (r8)
+		: : EV_HCALL_CLOBBERS6
+	);
+
+	*count = r4;
+
+	return r3;
+}
+
+/**
+ * ev_byte_channel_receive - fetch characters from a byte channel
+ * @handle: byte channel handle
+ * @count: (input) max num of chars to receive, (output) num chars received
+ * @buffer: pointer to a 16-byte buffer
+ *
+ * The size of @buffer must be at least 16 bytes, even if you request fewer
+ * than 16 characters, because we always write 16 bytes to @buffer.  This is
+ * for performance reasons.
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_byte_channel_receive(unsigned int handle,
+	unsigned int *count, char buffer[EV_BYTE_CHANNEL_MAX_BYTES])
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+	register uintptr_t r5 __asm__("r5");
+	register uintptr_t r6 __asm__("r6");
+	register uintptr_t r7 __asm__("r7");
+	register uintptr_t r8 __asm__("r8");
+	uint32_t *p = (uint32_t *) buffer;
+
+	r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_RECEIVE);
+	r3 = handle;
+	r4 = *count;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "+r" (r4),
+		  "=r" (r5), "=r" (r6), "=r" (r7), "=r" (r8)
+		: : EV_HCALL_CLOBBERS6
+	);
+
+	*count = r4;
+	p[0] = cpu_to_be32(r5);
+	p[1] = cpu_to_be32(r6);
+	p[2] = cpu_to_be32(r7);
+	p[3] = cpu_to_be32(r8);
+
+	return r3;
+}
+
+/**
+ * ev_byte_channel_poll - returns the status of the byte channel buffers
+ * @handle: byte channel handle
+ * @rx_count: returned count of bytes in receive queue
+ * @tx_count: returned count of free space in transmit queue
+ *
+ * This function reports the amount of data in the receive queue (i.e. the
+ * number of bytes you can read), and the amount of free space in the transmit
+ * queue (i.e. the number of bytes you can write).
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_byte_channel_poll(unsigned int handle,
+	unsigned int *rx_count,	unsigned int *tx_count)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+	register uintptr_t r5 __asm__("r5");
+
+	r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_POLL);
+	r3 = handle;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "=r" (r4), "=r" (r5)
+		: : EV_HCALL_CLOBBERS3
+	);
+
+	*rx_count = r4;
+	*tx_count = r5;
+
+	return r3;
+}
+
+/**
+ * ev_int_iack - acknowledge an interrupt
+ * @handle: handle to the target interrupt controller
+ * @vector: returned interrupt vector
+ *
+ * If handle is zero, the function returns the next interrupt source
+ * number to be handled irrespective of the hierarchy or cascading
+ * of interrupt controllers. If non-zero, specifies a handle to the
+ * interrupt controller that is the target of the acknowledge.
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_int_iack(unsigned int handle,
+	unsigned int *vector)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+	register uintptr_t r4 __asm__("r4");
+
+	r11 = EV_HCALL_TOKEN(EV_INT_IACK);
+	r3 = handle;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3), "=r" (r4)
+		: : EV_HCALL_CLOBBERS2
+	);
+
+	*vector = r4;
+
+	return r3;
+}
+
+/**
+ * ev_doorbell_send - send a doorbell to another partition
+ * @handle: doorbell send handle
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_doorbell_send(unsigned int handle)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+
+	r11 = EV_HCALL_TOKEN(EV_DOORBELL_SEND);
+	r3 = handle;
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "+r" (r3)
+		: : EV_HCALL_CLOBBERS1
+	);
+
+	return r3;
+}
+
+/**
+ * ev_idle -- wait for next interrupt on this core
+ *
+ * Returns 0 for success, or an error code.
+ */
+static inline unsigned int ev_idle(void)
+{
+	register uintptr_t r11 __asm__("r11");
+	register uintptr_t r3 __asm__("r3");
+
+	r11 = EV_HCALL_TOKEN(EV_IDLE);
+
+	__asm__ __volatile__ ("sc 1"
+		: "+r" (r11), "=r" (r3)
+		: : EV_HCALL_CLOBBERS1
+	);
+
+	return r3;
+}
+
+#endif